In 1941 the Soviet Union and the USA had entered the war on the side of the Allies. Stalin insisted that Britain and the USA should help the Russians by invading the continent of Europe and opening a 'Second Front' against Germany, so as to draw off German strength from the war in the Soviet Union. American leaders talked of landing in France in 1942 even though they had not yet built up their army, but the British feared a heavy defeat and their view seemed to be confirmed by the costly failure of a big raid on Dieppe in 1942, with the loss of many Canadian troops. Reluctantly President Roosevelt agreed to Churchill's plan to gain a victory by landing in French North Africa. The plan was codenamed 'Operation Torch'.

In November 1942 the Americans and British, both under the American commander General Eisenhower, landed from the sea in Morocco and Algeria. The Allies were worried about resistance from the French troops stationed there since Vichy France had proved itself loyal to the Axis. But there was only limited French resistance. The Germans rushed troops by air to Tunisia and defeated two British attempts to take Tunisia. A hard campaign of several months followed, to force the Germans out.

Rommel and his Afrika Korps planned to cripple the Allied Forces before Montgomery could attack from the Mareth Line. The Americans were defeated and they fell back to the next line of mountains. Rommel hoped to drive the Allies right out of Tunisia by a daring thrust through Tebessa, but he was ordered to drive through Thala, where Allied reinforcements happened to be assembled. Rommel captured the Kasserine Pass, but his troops were held at Thala and he had to withdraw in the Battle of the Kasserine Pass.

The Allies then built up their Forces to twice the number of German troops and six times their number of tanks. Montgomery worked his way round the Mareth Line, a very strong position. The American General Patton helped with attacks. The Americans and British then pushed forward. The Germans and Italians held on obstinately but eventually the Allied Forces overran them and took Tunisia. About 175 000 prisoners were taken. After three years of desert warfare the Axis powers had at last been driven out of Africa (May 1943).