John de Montagu, 1st Baron Montagu

John de Montagu, 1st Baron Montagu (c. 1330–c. 1390), was a younger son of William Montagu, 1st Earl of Salisbury, and Catherine Grandison, and brother of the 2nd earl. Froissart records him at the Siege of Calais in 1349, and in 1357 he was summoned to parliament as Baron Montagu.

He married Margaret de Monthermer, heiress of Thomas, 2nd Baron Monthermer; their son John inherited the earldom of Salisbury from his uncle in 1397 and became the 3rd earl.