Ilja Keizer (née Laman; born 26 February 1944) is a retired middle-distance runner from the Netherlands who competed at two Olympic Games.
Laman finished second behind Anne Smith in the 880 yards event at the 1966 WAAA Championships.
Under her married name of Keizer, she competed at the 1968 and 1972 Summer Olympics in the 800 m and 1500 m, respectively, and finished in sixth place in 1972.
In 1970 and 1972, Keizer was selected as the . Her personal bests were 2:02.2 in the 800 m (1968) and 4:05.13 in the 1500 m (1972).