I by Day, You by Night (German: Ich bei Tag und du bei Nacht) is a 1932 German musical comedy film directed by Ludwig Berger and starring Käthe von Nagy and Willy Fritsch. It was shot at the Babelsberg Studios and on location at the Sanssouci Palace in Potsdam. The film's sets were designed by the art director Otto Hunte. It premiered in Berlin on 29 November 1932.

As was common at the time separate English- and French-language versions were released, both directed by Berger. The British version Early to Bed was co-produced with Gaumont British. The plot is very similar to the 1933 American film, Rafter Romance and its 1937 remake, Living on Love, though these films are based on a 1932 novel also named "Rafter Romance".