Once You Give Away Your Heart (German: Wenn du einmal dein Herz verschenkst) is a 1929 German comedy film directed by Johannes Guter and starring Lilian Harvey, Igo Sym, and Harry Halm. Made at the time of the conversion to sound film, it was released in both sound and silent versions.

The film's art direction was by Heinz Fenchel and Jacek Rotmil. It was shot at the Babelsberg Studios and on location in Tenerife and on board a cargo steamer sailing from Hamburg.