Sandy Block, also credited as Sid Block (January 16, 1917 - October 1985) was an American jazz bassist.

Block played violin as a child, and grew up in Cleveland and Brooklyn. He picked up bass in high school and worked professionally in big bands from the late 1930s. He worked with Van Alexander, Chick Webb, Alvino Rey, and Tommy Dorsey and recorded with Louis Armstrong and Ella Fitzgerald. He played with Charlie Parker on the only television appearance Parker ever made.

After the 1950s Block worked extensively as a studio musician, including for folk ensembles such as The Greenbriar Boys. He played with Jimmy McPartland and Johnny Costa, but went into semi-retirement after the 1960s.