Brigadier Lewis Ernest Stephen Barker, CBE, DSO, MC (5 May 1895 – 13 December 1981) was a career Australian Army officer, who saw distinguished service in both of the world wars.

For valiant actions in late September 1918, during the Hundred Days Offensive, he received the Military Cross, the citation for which reads: While acting as Liaison Officer with infantry on the 28th September, 1918, west of Bellicourt, with one other as bayonet man, he bombed his way along a trench under heavy machine-gun fire, reestablished an important flanking post, and reconnoitred across a difficult enemy pocket on the flank, getting valuable information.

He served in the army, and after various promotions took command of fortresses at Newcastle, New South Wales.

Barker soon assumed command of the artillery of the 7th Division, New Guinea Force and I Corps.

He was then in charge of the artillery of the First Army, and was appointed a Commander of the Order of the British Empire in December 1943.