Sidney J. Marcus (February 5, 1928 – October 27, 1983) was a Georgia (U.S.) legislator from Atlanta's 26th district, now the 106th district, who served in the Georgia General Assembly from 1968 until his death in 1983. He served on several committees: Health and Ecology, on which he was chairman; Ways and Means; and Rules. For several years, Marcus was chairman of Fulton County delegation. He was also an unsuccessful candidate for Mayor of Atlanta in 1981, defeated by Andrew Young. He was a noted Atlanta politician, and active in the Jewish community.
His accomplishments included helping to stop the I-485 freeway which threatened several intown neighborhoods (leading to the park named in his honor).
Sidney Marcus attended Atlanta public schools and graduated from the University of Georgia in 1948, as a member of [[Fraternities and sororities|Zeta Beta Tau fraternity]]. He was a 1955 graduate of the Emory University School of Law.
Marcus married Charlotte Glyck of Waycross, GA, and they had three children, Robyn, Bradley and Beth.