William Foulis may refer to:Sir William Foulis, 4th Baronet (1659–1741), of the Foulis baronets Sir William Foulis, 5th Baronet, of the Foulis baronets Sir William Foulis, 6th Baronet (1729–1780), of the Foulis baronets Sir William Foulis, 7th Baronet (1759–1802), of the Foulis baronets Sir William Foulis, 8th Baronet (1790–1845), of the Foulis baronets Sir William Liston-Foulis, 8th Baronet (1812–1858), of the Foulis baronets Sir William Liston-Foulis, 10th Baronet (1869–1918), of the Foulis baronets