Alpha Sigma Delta () was an American collegiate sorority that formed in 1918 at University of California, Berkeley. It was absorbed by Lambda Omega in April 1932.
Alpha Sigma Delta started as a sorority called the Iaqua Club at University of California, Berkeley in 1918. Iaqua Club changed its name to Alpha Sigma Delta in 1919.
In 1925, Alpha Sigma Delta became a regional sorority with the creation of its Beta chapter at the University of California, Los Angeles. It became a national sorority in 1928 with the chartering of the Gamma chapter at Colby College in Waterville, Maine. A total of five chapters were established; although only the names of four are known.
In April 1932, Alpha Sigma Delta was absorbed by Lambda Omega (), another sorority that was also established at the University of California, Berkeley. In September 1933, Lambda Omega was absorbed by Theta Upsilon. In turn, Theta Upsilon merged into Delta Zeta in 1962.
Alpha Sigma Delta's badge was a shield of red enamel, bearing the Greek letters , vertically. The sorority's colors were gold and white. Its quarterly magazine was The Crown.
The known chapter list follows, with inactive chapters noted in italics.