Robert Marsack Manser (10 October 1880 – 15 February 1955) was an English first-class cricketer. Manser represented Hampshire in a single first-class match against the touring South Africans at the Municipal Ground, Alton in 1904. In 1909 Manser joined Dorset, representing the club in the 1909 Minor Counties Championship. Manser made his Dorset debut against the Surrey Second XI, playing regularly for the county until the 1913 season. Manser died at Parkstone, Dorset on 15 February 1955.