| 2 January | US 163rd Inf. Regiment, 41st Inf. Div., fresh from Australia, took over roadblocks outside Sanananda, relieving battered Australian troops, Papua New Guinea. |
| 10 January | Soviets begin offensive against Germans at Stalingrad. |
| 14 January | Churchill and Roosevelt begin the Casablanca conference. |
| 15 January | Pentagon building completed as US War Department headquarters after only 16 months of construction, costing approx $83 million. |
| 18 January | Warsaw Ghetto Uprising against Germans captors begins [18 Jan-16 May]. |
| 18 January | Red Army takes German fortifications south of Lake Ladoga [Operation Spark], opening a corridor to Leningrad, partially lifting the siege. |
| 22 January | Japanese resistance overcome at Sanananda, the last Japanese stronghold on Papua New Guinea, relieving the threat of invasion of Australia. |
| 23 January | British Eighth Army under Montgomery takes Tripoli, in a defeat for Gen. Erwin Rommel's Afrika Korps. |
| 27 January | The first batch of Ka-Bar knives [Knife, Fighting and Utility] shipped to the USMC from Union Cutlery Company of Olean, NY. |
| 29 January | Marine Corps Women's Reserve [MCWR] created with the slogan 'Free A Man To Fight!'. |
| 31 January | General Paulus, the German Sixth Army commander at Stalingrad, defies Hitler, surrenders the remnants of his force, a mere 12,000 survivors. |
| 2 February | Remaining Sixth Army Germans surrender at Stalingrad, Hitler's first big defeat. |
| 2 February | Operation Star: Red Army offensive begins, threatening to recapture the cities of Belgorod, Kharkov and Kursk. |
| 3 February | While helping others to reach safety, Four Chaplains of the US Army go down with USAT Dorchester after German torpedo attack on the troop ship. |
| 9 February | Allied forces capture Guadalcanal, Solomon Islands. |
| 11 February | General Dwight Eisenhower is named commander of the Allied armies in Europe. |
| 14 February | Battle of Kasserine Pass between US and German armored forces begins with 4 days of fighting around Sidi Bou Zid and Sbeitla, Tunisia [14-17 Feb]. |
| 16 February | Germans withdraw and Soviet troops reconquer Kharkov, but cannot hold on in the Third Battle of Kharkov later in Feb-Mar 1943. |
| 18 February | German Propaganda Minister Joseph Göbbels declares 'Total War' against the Allies, in a Berlin speech. |
| 18 February | Six key members of the White Rose anti-Nazi movement [students and professor from University of Munich] arrested in Germany. |
| 19 February | Third Battle of Kharkov begins offensive operations by German forces agains the Red Army in the vicinity of Kharkov [19 Feb-15 Mar]. |
| 19 February | Mass armor/infantry attack by Germans under Rommel against US II Corps breaks through the mountains at Kasserine Pass, Tunisia, a spectacular success [19-20 Feb]. |
| 22 February | Members of White Rose anti-Nazi movement executed in Germany. |
| 22 February | An American amphibious force lands on the Russell Islands, sixty miles northwest of Guadalcanal in the Solomons. |
| 28 February | Operation Gunnerside: Six Norwegians led by Joachim Ronneberg attack the German-controlled heavy water plant Vemork, destroying key facility of German atomic program. |
| 1 March | Gen. Heinz Guderian becomes the Inspector-General of the Armoured Troops for the German Army, responsible for panzer force strategy, tank design and production. |
| 2 March | Battle of the Bismark Sea: US and Royal Australian Air Force, and US Navy small craft sank eight Japanese transports and four destroyers [2-5 Mar]. |
| 3 March | During the London Blitz, 173 people killed in mob crush trying to enter the air-raid shelter at Bethnal Green tube station, the war's worst civilian disaster. |
| 5 March | RAF Bomber Command mounts a devestating attack on the Krupp factory in Essen, Germany using the new Oboe targeting system. |
| 6 March | Operation Capri: Rommel attacks Montgomery's forces at Medenine, Tunisia where a Mareth Line offensive was forming; attack repulsed and German forces withdraw north to Mareth Line. |
| 13 March | German forces liquidate the Jewish ghetto in Krakow, Poland. |
| 19 March | China Air Task Force [Flying Tigers] disbanded as Fourteenth Air Force established by special order of the President with General Claire Lee Chennault as commander. |
| 22 March | Population of Khatyn, Belarus [149 people, including 75 children] is locked in a shed and burnt to death by German forces, in retaliation for a partisan attack earlier the same day. |
| 26 March | Battle of the Komandorski Islands [Aleutians] as United States Navy forces intercept Japanese troops attempting to reinforce a garrison at Kiska. |
| 27 March | British Escort carrier HMS Dasher destroyed in the Firth of Clyde by an accidental aviation fuel explosion, killing 379 of the crew of 528. |
| 28 March | Port of Naples, Italy: ammunition ship Caterina Costa, loaded with supplies for Italian forces in Africa, explodes killing 600 plus 3000 injured. |
| 1 April | Meat, fats, canned goods, and cheese rationed in US. Wages, salaries, and prices are frozen. |
| 2 April | Hermann Göring orders every German adult to participate in anti-air raid civil defense, manning anti-aircraft artillery and similar duties. |
| 13 April | Radio Berlin reveals the German army discovery of mass graves of Poles massacred by Soviets in the Katyn Forest. |
| 14 April | US Navy Fleet Radio Unit Pacific intercepts message NTF131755 (decrypted by Project Magic) enabling mission 4 days later to shoot down Japanese Combined Fleet Admiral Isoroku Yamamoto. |
| 18 April | Japanese Combined Fleet Admiral Isoroku Yamamoto killed when intercepted and shot down over Bougainville by 18 P-38 aircraft, the longest such mission of the war. |
| 19 April | On the first day of Passover, 2000 German troops marched into the Warsaw Ghetto to round up remaining Jews but were attacked and routed by the residents. |
| 21 April | Luftwaffe blitz raid on Aberdeen, Scotland is the worst there for WW II. 127 bombs dropped, 98 civilians and 27 servicemen killed, heavy property damage. |
| 4 May | Last major North Atlantic U-boat Wolf Pack attack of WW II: 12 Allied ships sunk from eastbound Convoy ONS-5, six German submarines sunk out of 60 attackers [4-6 May]. |
| 9 May | Japanese troops in Changjiao, Hunan, China kill more than 30,000 civilians and rape thousands of women [Changjiao Massacre, 9-12 May 1943], one of many Japanese war crimes in WW II. |
| 11 May | American troops invade Attu in the Aleutian Islands, beginning campaign to expel occupying Japanese forces [11-29 May]. |
| 12 May | Organized Axis resistance in North Africa ends. |
| 12 May | Third Washington Conference, the Trident Conference between Franklin D. Roosevelt and Winston Churchill begins in Washington, DC [12-27 May]. |
| 13 May | Allied victory in Tunisia: German Afrika Korps and Italian troops surrender. |
| 16 May | Royal Air Force No. 617 Squadron [The Dambusters] destroyed the Möhne and Eder dams on the Ruhr, causing catastrophic flooding [Operation Chastise, 16–17 May]. |
| 16 May | Warsaw Ghetto Uprising ends with liquidation of the poorly equipped Jewish resistance by German Troop. |
| 17 May | US Army contracts with University of Pennsylvania's Moore School of Electrical Engineering to develop ENIAC computer. |
| 17 May | 8th Air Force B-17F Flying Fortress named Memphis Belle becomes the first plane to complete a 25-mission tour of duty. |
| 23 May | Adm. Döntiz, commander of the German Navy, calls off the Battle of the Atlantic, recognizing that the U-boat is no longer an effective weapon. |
| 24 May | Dr. Josef Mengele, German SS officer and physician, becomes the medical officer at Auschwitz-Birkenau concentration camp. |
| 29 May | Remaining Japanese forces on Attu, Aleutian Islands, stage surprise suicidal banzai charge at Massacre Bay, one of the largest such attacks experienced in the Pacific. |
| 2 June | 99th Pursuit Squadron (Tuskegee Airmen) flies first combat mission, over Italy. |
| 16 June | Last Jewish residents of Berlin are deported to Theresienstadt concentration camp, reducing to zero the pre-Nazi Jewish population estimated at 186,000. |
| 16 June | Over Guadalcanal in the Solomons, 77 Japanese fighters and bombers downed by Allied pilots with 17 more destroyed by ships and antiaircraft guns. US lost only six planes. |
| 20 June | Operation TOENAILS opens with Marines landing at Segi Point on Vangunu Island, southeast of New Georgia. |
| 30 June | Invasion of New Georgia, Central Solomons, with Munda as its objective. |
| 1 July | US Women's Army Corps [WAC] established by Congress. |
| 5 July | Battle of Kursk (Operation Citadel) begins, last German offensive in Russia and largest tank battle [5-19 July]. |
| 6 July | US and Japanese naval forces fight the Battle of Kula Gulf off Kolombangara, in the New Georgia Islands group of the Solomon Islands. |
| 9 July | US-British invasion of Sicily begins [night of 9-10 Jul]. |
| 10 July | Montgomery's British Eighth Army takes Syracuse on the first day of the invasion if Sicily, Italy. |
| 10 July | US Army Air Force begins raids against the Kurile Islands, the Northern Territories of Japan, about 650 miles west of the Aleutians. |
| 12 July | Tank battle at Prokhorovka, during the Battle of Kursk, greatest tank battle of WW II, unsurpassed until Operation Desert Storm in 1992. |
| 13 July | Battle of Kolombangara in the Solomon Islands; US Navy prevents Japanese from landing reinforcements on New Georgia, although Japanese ships escaped and US had 3 seriously damaged. |
| 19 July | First Allied bombing of Rome, Italy. |
| 19 July | Battle of Kursk ends with tremendous German losses, followed by Soviet offensive that continued westward until the fall of Berlin 2 May 1945. |
| 24 July | Start of the Battle of Hamburg [Operation Gomorrah], an eight day/night air campaign that destroyed large zones of the city by firestorm. |
| 24 July | Gen. Patton's Seventh Army secures Palermo, Sicily. |
| 25 July | As defeats pile up, Mussolini replaced by Badoglio as Italian Premier. |
| 1 August | Ploesti Raid: 178 B-24 Liberator bombers flew over 1200 miles from a base in North Africa to Ploesti, Romania for a daring, low level attack on oil production facilities. |
| 2 August | Revolt by inmates of Treblinka death camp; guards and one SS officer killed and over 200 hundred inmates escaped; a few avoided death or recapture. |
| 2 August | Future US President John F. Kennedy's motor torpedo boat PT-109 is rammed by a Japanese destroyer in the Solomon Islands. |
| 3 August | Red Army launches Belgorod-Kharkov Strategic Offensive Operation [Aug 3-23], forcing German retreat across Dnepr River. |
| 5 August | Women's Air Force Service Pilots [WASP] formed, consolidating the WAFS and WFTD organizations. |
| 5 August | Capture of Munda Point Airfield at New Georgia, Central Solomon Islands by US Army troops. |
| 6 August | Battle of Vella Gulf: US Navy defeats Japanese convoy off Kolombangara in the Central Solomons. |
| 15 August | In the Aleutians, US troops land on Kiska Island to retake it from the Japanese ([5-24 Aug]. |
| 17 August | RAF attack (Operation Hydra) on German V-2 rocket facility at Peenemünde demolishes the factory. Over 500 Allied bombers dropped 1600 tons of explosives and 280 tons of incendiaries. |
| 17 August | First Quebec Conference [QUADRANT] held between British, Canadian and United States governments [August 17-24]. |
| 17 August | Just hours after the last German units evacuated the city, elements of the US 3d Infantry Division's 7th Infantry Regiment enter Messina, Sicily, the final objective of Operation Husky. |
| 19 August | Quebec Agreement: British atomic research became part of the US Manhattan Project until after the war; British and Canadian scientists moved to the US to take part. |
| 21 August | Southeast Asia Command (SEAC) set up as Supreme Allied command for Asia, with British Admiral Lord Louis Mountbatten as Supreme Allied Commander. |
| 24 August | Aleutian campaign ends as US troops find Kiska Island uninhabited and declare the island secure, the Japanese having withdrawn secretly. |
| 25 August | Bairoko Harbor, Japanese strong point on New Georgia, 8 miles north of Munda, falls to US troops. |
| 3 September | Allied invasion of Southern Italy begins with British landings in Calabria. |
| 8 September | Italian army surrenders, German army in Italy takes control and fights on. |
| 9 September | With Italian cooperation, Operation SLAPSTICK lands 3600 men of the British 1st Paratroop Division at the port of Taranto in the Italian heel. |
| 9 September | Operation AVALANCHE, invasion of Italy at Salerno uses 450 ships to land a total of about nine divisions. |
| 10 September | Germans occupy Rome, post troops around Vatican City; Mussolini becomes head of state in German-occupied Northern Italy. |
| 12 September | Germans attack the entire Allied front at the Salerno beachhead, an attempt to force the Allies off the beach, back to the sea, but Allies hold [12-14 Sep]. |
| 16 September | Malaya Zemlya enclave of Novorossiysk port on the Black Sea, after holding out against Wehrmacht for 225 days, liberated by the Red Army. |
| 18 September | US Army, Marine, and New Zealand troops land on Vella Lavella, fifteen miles northwest of Kolombangara, between New Georgia and Bougainville, Central Solomons. |
| 20 September | Italy bisected as U.S and British forces meet at Eboli. |
| 21 September | In the most bitter combat of the New Georgia campaign [Central Solomons], Japanese lose 600 men in an unsuccessful defense of Arundel Island, withdraw on 22 Sep. |
| 22 September | Operation TOENAILS completed, with the occupation by US troops of all important islands in the New Georgia group, Central Solomons. |
| 27 September | Airfields near Foggia, on the east coast of Italy, captured by British, giving Allied air power the base to hit targets in France, Germany and the Balkans. |
| 28 September | More than 9000 Japanese troops escape from Central Solomons to southern Bougainville in a well-organized evacuation effort [28 Sep-3 Oct]. |
| 1 October | American forces enter Naples, Italy, the first major European city to be liberated during WW II. |
| 4 October | Heinrich Himmler speaks to secret meeting of SS officers, in Poznan [Posen], Poland, openly describing the Nazi effort to exterminate the Jewish people. |
| 6 October | More than four hundred rabbis arrive in Washington, DC to plead for US government action to save Jews from Hitler; Roosevelt administration unresponsive. |
| 10 October | Double Tenth Incident: Singapore's Japanese Military Police (Kempeitai) arrest and torture 57 civilians, suspecting them in the Operation Jaywick Australian commando raid on Singapore Harbor. |
| 13 October | Italy's new government, now siding with the Allies, declares war on Germany. |
| 14 October | Schweinfurt Raid, Black Thursday: US 8th Air Force sends more than 250 B-17 Flying Fortress bombers to destroy ball-bearing factories. |
| 17 October | At Gothenburg, about 10,000 seriously wounded and sick German and British POWs, about half from each side, make up the first British-German prisoner exchange of WW II [17-21 Oct]. |
| 18 October | Third Moscow Conference: US Britain, and the Soviets discuss the progress of the war against Germany and post-war methods to ensure peace [18 Oct-11 Nov]. |
| 19 October | Chinese and Suluks revolt against Japanese in North Borneo. |
| 22 October | German industrial and population center of Kassel targeted by 569 RAF bombers that dropped more than 1,800 tons of bombs, causing heavy damage in a firestorm. |
| 25 October | American and New Zealand troops land at Mono and Stirling, Treasury Islands, south of Bougainville [25-27 Oct]. |
| 27 October | American and New Zealand troops land on Choiseul, a large island near Bougainville. |
| 1 November | US Marines land at Empress Augusta Bay, on west coast of Bougainville in the Solomon Islands [Operation Goodtime]. |
| 2 November | Battle of Empress Augusta Bay off Bougainville is inconclusively fought in the early morning hours. |
| 2 November | At Winter Line in Italy, US 5th Army & British 10th Corps reach Garigliano River; 5th Army prepares to cross Volturno River; British 8th Army begins major assault across Trigno River. |
| 3 November | US 8th Air Force stages 500 bomber raid that heavily damages Wilhelmshafen harbor, Germany. |
| 4 November | US 5th Army in Italy captures Monte Massico, Monte Croce, Venafro and Rocavirondola. Germans withdraw to the Reinhard Line. |
| 4 November | Germans destroyed labor camp at Poniatowa, Poland. About 15,000 Jews were shot or burned to death. |
| 6 November | Soviet troops of the 1st Ukrainian Front liberate Kiev from the German Army Group South. |
| 15 November | German SS leader Heinrich Himmler orders Gypsies and those of mixed Gypsy blood to be 'on the same level as Jews and placed in concentration camps'. |
| 16 November | Flying from Britain, 160 American bombers strike hydro-electric power facility and heavy water factory in German-controlled Vemork, Norway, destroying key facililty of German atomic program. |
| 18 November | Intensive RAF Bomber Command attack on Berlin, Germany begins with a 440 plane mission that causes only light damage, killing 131 while RAF loses 9 aircraft and 53 aviators. |
| 20 November | Makin, Tarawa [Gilbert Islands] invasion by US amphibious force [20-23 Nov]. |
| 21 November | Hitler appoints Luftwaffe Field Marshal Albert Kesselring as commander of all German forces in Italy. |
| 22 November | First Cairo Conference between Churchill, Roosevelt, and Chinese leader Chiang Kai-shek [November 22-26]. |
| 23 November | Deutsche Opernhaus, Kaiser Wilhelm Memorial Church, and many other buildings destroyed by a 764 aircraft RAF bombing raid on Berlin [22-23 Nov]. |
| 25 November | Battle of Cape St. George between Buka and New Ireland, off Papua New Guinea, fought by US and Japanese naval forces. |
| 28 November | Roosevelt, Churchill, Stalin meet at Teheran Conference in Iran. |
| 1 December | Declaration of the Three Powers made at the completion of the Tehran Conference, the first personal meeting of Roosevelt, Stalin, and Churchill. |
| 2 December | Luftwaffe conducts most successful raid on Allied shipping since Pearl Harbor, sending 105 Ju88 bombers to strike the port of Bari, Italy sinking 17 ships. |
| 3 December | German Reichsmarshall Hermann Göring orders intensification of the Luftwaffe's bombing of Britain. |
| 3 December | RAF Bomber Command raid on Leipzig, Germany, causes over 1000 civilian casualties [Dec 3-4]. |
| 4 December | Second Cairo Conference with Roosevelt, Churchill, and Ismet Inönü of Turkey [Dec 4-6]. |
| 12 December | Soviet Union and Czechoslovakia meet at the Kremlin and sign a mutual assistance treaty. |
| 14 December | 300 US planes attack German controlled airfields in Greece and merchant ships in the Port of Piraeus. |
| 15 December | US forces in the Solomon Islands land on the Arawe Peninsula, New Britain. |
| 24 December | Major offensive launched by Soviet 1st Ukrainian Front, shattering the lines of the German 4th Panzer Army. |
| 25 December | Battleship Yamato, the pride of the Japanese Navy, and her task group intercepted by USS Skate (SS-305). Skate's torpedo attack damaged Yamato but did not sink her. |
| 26 December | German battleship Sharnhorst sunk off North Cape. |
| 28 December | Fighting at Ortona, Italy [Little Stalingrad] ends with Allied victory following difficult street fighting and house to house combat. |
| 28 December | Shortage of workers in Nazi Germany motivates an order by Heinrich Himmler to reduce the inmate death rate in forced labor camps. |
| 29 December | Major Red Army victory west of Kiev forces the withdrawal of 200,000 German troops west toward Poland. |
| 30 December | US First Marines capture key airfield at Cape Gloucester, New Britain. |
