The film unfolds in two distinct parts, separated by an intermission.
Part I
In 1935, the life of T. E. Lawrence, played by Peter O'Toole, is tragically cut short in a motorcycle accident. At his memorial service at St. Paul's Cathedral, reporters seek to unravel the complexities of this remarkable man, but they find themselves at a loss. During World War I, Lawrence stands out as an unconventional British Army lieutenant stationed in Cairo, known primarily for his insolence and his deep understanding of the Bedouin culture. Despite the objections from General Murray (played by Donald Wolfit), Mr. Dryden (portrayed by Claude Rains) from the Arab Bureau sends Lawrence to evaluate the potential of Prince Faisal (played by Alec Guinness) in his rebellion against the Turks.
While making his journey, Lawrence witnesses the harsh realities of Bedouin life when his guide is killed by Sherif Ali (represented by Omar Sharif) over a dispute regarding a well. Upon arrival, Lawrence meets Colonel Brighton (played by Anthony Quayle), who enforces a cautious approach. However, Lawrence shows defiance by engaging Faisal directly, sparking the prince's curiosity with his bold knowledge. Brighton, suggesting a retreat after a major setback, is challenged by Lawrence, who proposes an audacious surprise attack on Aqaba. If successful, this would establish a crucial supply port for the British. Despite the town being heavily fortified at sea, it is vulnerable on the landward side, and with Lawrence's persuasion, Faisal agrees to contribute fifty men, led by a doubtful Sherif Ali. Two orphans, Daud (John Dimech) and Farraj (Michel Ray), join him as aides.
The group embarks on a daunting expedition across the Nefud Desert, known for being virtually insurmountable. As they journey relentlessly day and night in search of water, they unwittingly leave behind Gasim (I. S. Johar), who succumbs to exhaustion. Determined, Lawrence risks his own safety by backtracking to save Gasim, winning over Sherif Ali in the process. Eventually, he enlists Auda Abu Tayi (Anthony Quinn), a powerful tribal leader, to join their cause against the Turks. Conflict arises when one of Ali’s followers kills a member of Auda’s tribe, threatening their fragile alliance. To maintain unity, Lawrence takes the extreme step of executing the murderer himself, only to find that it is Gasim. This sacrifice solidifies their alliance, enabling them to triumph over the Turkish forces.
After relaying the news of victory to Mr. Dryden and the new commander, General Allenby (Jack Hawkins), Lawrence faces another tragedy during their crossing of the Sinai Desert when Daud tragically dies in quicksand. Promoted to major, he receives resources to aid the Arabs but struggles internally with his act of execution—confessing enjoyment to Allenby, who dismisses Lawrence’s concerns about British intentions in Arabia.
Part II
Lawrence embarks on a relentless guerrilla campaign, targeting Turkish supply lines by derailing trains and disrupting operations. His actions catch the attention of American war correspondent Jackson Bentley (Arthur Kennedy), who helps elevate Lawrence's fame. However, in a disastrous raid, Farraj suffers grave injuries, and feeling compelled to save him from torture, Lawrence makes the heart-wrenching decision to end Farraj’s life.
When scouting the city of Daraa with Ali, Lawrence is captured by the Turkish Bey (José Ferrer), who subjects him to humiliating and brutal interrogation. Following this traumatic experience, Lawrence finds himself in Jerusalem, where Allenby pressures him to spearhead an advance on Damascus. By now, Lawrence is a changed man, tormented by his past actions, yet he ultimately agrees to lead the effort.
He assembles an army comprised mainly of ruthless fighters, driven more by greed than by a sense of duty to the Arab cause. Amid their assaults, they confront a column of Turkish soldiers guilty of atrocities against the people of Tafas. Amid the chaos, one of Lawrence’s men demands, > "No prisoners!" When Lawrence hesitates, the man charges alone into danger and is killed. This spurs Lawrence to echo the command, leading to a bloody massacre in which he actively participates.
Upon taking Damascus ahead of Allenby's forces, the newly-introduced Arab council struggles to govern effectively, succumbing to infighting and operational failures, ultimately relinquishing control to the British. Lawrence, now promoted to colonel, finds his role diminished and is promptly ordered home, feeling the weight of his disillusionment as he departs in a staff car, rendered obsolete by both Faisal and the British authorities.
