Roger de Mortimer, 2nd Earl of March (1328 – February 26, 1360) was an English nobleman and military commander during the Hundred Years War.

He was the son of Edmund de Mortimer, who was the son of Roger de Mortimer, 1st Earl of March. His mother was Elizabeth Badlesmere.

The Mortimer family lands and titles were lost after the first earl's revolt and death in 1330, which was followed the next year by the death of Roger's father. Roger thus grew up with uncertain prospects, and was to only gradually re-acquire the family honors.

Around 1342, he received back Radnor, and the next year the old family baronial seat at Wigmore.
As a young man he distinguished himself in the wars in France, fighting at Crecy and elsewhere in the campaign of 1347. Afterwards he was given livery of the rest of his lands, was one of the original Knights of the Garter, and was summoned to parliament as a baron in 1348.

In 1354, the sentence passed against his grandfather the first earl was reversed, and the next year he was summoned to parliament as Earl of March. Also in 1355 he received a number of important appointments, including Constable of Dover Castle and Warden of the Cinque Ports, and accompanied Edward III's expedition to France.

Around this time his grandmother, Joan de Genville, widow of the first earl, died, and Roger inherited her large estate, including Ludlow Castle, which was thereafter the Mortimer family seat.
In the following years he became a member of the royal council, and was appointed constable at the castles of Montgomery, Bridgnorth, and Corfe.

In 1359, and continuing into 1360, he was constable of Edward III's invasion of France, fighting in the failed siege of Reims and capturing Auxerre. The English forces then moved into Burgundy, where Roger died suddenly at Rouvray near Avallon.

Roger married Philippa Montacute, daughter of William Montacute, 1st Earl of Salisbury.