Dennis Michael Crosby (July 13, 1934- May 7, 1991) was an American actor, the son of singer and actor Bing Crosby, and the father of actress Denise Crosby. He committed suicide in 1991.

Dennis was the son of Bing Crosby and Dixie Lee Crosby , Bing Crosby's first wife. With his twin brother Phillip Crosby and his other brothers he attended Bellarmine Academy in Santa Clara. He graduated in 1952, and enrolled at Washington State College at Pullman.

In the late 1950's Dennis and his brothers often performed as the Crosby Brothers in nightclubs and on the Ed Sullivan Show, though Dennis Crosby reputedly wished to avoid such appearances.

While a young man Crosby performed military service in Germany.

In the 1950's he married Marilyn Miller Scott, and they had one daughter, Denise. In early 1958 they divorced, and Crosby subsequently married Pat Sheehan, a Las Vegas showgirl. The marriage to Sheehan and other details caused deep embarrassment for both him and his famous father during a widely-reported and sensational paternity suit for custody of his daughter Denise.

In 1958 Sheehan gave birth to a son, also named Dennis Michael Crosby. Sometime later his marriage to Sheehan ended, and in 1963 while working in Los Angeles for Bing Crosby Productions, he met and later married Arlene Crosby, with whom he had three daughters. They divorced in 1991.

On December 26, 1989, Crosby's younger brother Lindsay committed suicide by a shotgun blast to the head. Deeply distraught by his brother's passing and his recent divorce and grappling with alcoholism, Dennis Crosby committed suicide on May 7, 1991 in Novato, California, also with a shotgun.