During World War I Lawrence, who had been promoted to captain in 1913, served with the Suffolks as part of the 163rd Norfolk and Suffolk Brigade at Gallipoli from the Landing at Suvla Bay in August until the evacuation from Gallipoli in December 1915. He was promoted to major whilst in action at Gallipoli and then to temporary lieutenant colonel after the battalion was evacuated to Egypt, commanding the battalion. He transferred to become the commanding officer of the 1/7 battalion Cheshire regiment in 1916, seeing action during the Sinai and Palestine Campaign at the First Battle of Gaza in early 1917, capturing the hillside position at Ali Muntar for which he was awarded the Distinguished Service Order (DSO). He fought at Second Gaza and in the Battle of Beersheba later in 1917 before leading his battalion into Jerusalem in the advance guard.