Cairo in 1917: Lieutenant Lawrence, a 29-year-old bored general staffer, is considered a weird outsider by his comrades. When Dryden, a cynical diplomat from the Arab Bureau, offers him a mission in the Arabian desert, Lawrence immediately accepts. As a contact officer between the British and the Arabs he is supposed to observe the progress of the Arab rebellion against the Turks, to find out about the strength of the tribes fighting under prince Feisal and to learn more about Feisal´s long-term plans for Arabia. Once in the desert, he becomes a friend of Sherif Ali Ben El Kharish who first considers him merely just to be another desert-loving Englishman. With a combination of diplomacy and bribery, Lawrence unites the rival Arab factions of Prince Feisal and Auda Abu Tayi for a war against the Turks.
After successfully capturing the fortress of Acaba, the Arabs hail him as the new Saviour. His superiors instead consider him a useful pawn to maintain the Arab rebellion against the Axis Powers. Meanwhile Lawrence has come to like his new found fame and starts on a spying mission to Deraa. But he has pushed his luck to far. He is recognized, taken as prisoner by the Turks and tortured brutally. After Ali has freed him, Lawrence returns to Cairo to ask his officers for "an ordinary post for an ordinary man". But general Allenby manages to change his mind promising to leave Damakus after its conquest to the Arabs.
With new Arab troops Lawrence heads to Damaskus. On their way they meet Turkish troops who only a short while ago massacred the people of a village. In a sudden surge of rage Lawrence orders his men to attack the Turks giving out the motto “No Prisoners!”.
They conquer Damaskus and lose it again instantly because in the moment of victory the old rivalries between the Arabs arise anew and the Bedouines prove to be incapable of running a large city such as Damaskus. Auda decides to return to the desert whereas Ali intends to learn politics.
When visiting a military hospital whose personnel has fled, leaving the prisoners and patients on their own, Lawrence realizes that all his efforts were in vain and he breaks down with hysteric laughter. His commanders and prince Feisal have only been waiting for the break-up of the Arabic Council and share the booty. Since there is nothing left to do for him Lawrence asks to be transferred back to England.