Mariclare Costello (gebore 3 Februarie 1936) is 'n Amerikaanse aktrise. Sy is bekend vir haar rolle in die rolprente Let's Scare Jessica to Death (1971), Ordinary People (1980), The Adventures of Buckaroo Banzai Across the 8th Dimension (1984), en Indecent Proposal (1993).
- 1970: Pound
- 1971: Let's Scare Jessica to Death
- 1980: Ordinary People
- 1984: The Adventures of Buckaroo Banzai Across the 8th Dimension
- 1993: Indecent Proposal
- 1975: Sunshine
- 1977: The Fitzpatricks
- 1972: Going Where I've Never Been: The Photography of Diane Arbus
- 1974: After the Fall
- 1974: The Execution of Private Slovik
- 1977: A Sensitive, Passionate Man
- 1980: The Boy Who Drank Too Much
- 1981: Coward of the County
- 1982: Skeezer
- 1985: Heart of a Champion: The Ray Mancini Story
- 1987: American Harvest
- 2000: Shadow of the Blair Witch
