Night unto Night is a 1949 American drama film directed by Don Siegel and written by Kathryn Scola. It is based on the 1944 novel by Philip Wylie. The film stars Ronald Reagan, Viveca Lindfors, Broderick Crawford, Rosemary DeCamp, Osa Massen and Art Baker. The film was released by Warner Bros. on June 10, 1949.

Fifteen years later, Siegel directed Reagan's final film, 1964's The Killers.