They Knew What They Wanted is a 1940 film directed by Garson Kanin, written by Robert Ardrey, and starring Carole Lombard, Charles Laughton and William Gargan.

It is based on the 1924 Pulitzer Prize winning play They Knew What They Wanted by Sidney Howard.

When visiting San Francisco, Tony Patucci, an aging illiterate winegrower from the Napa Valley, sees waitress Amy Peters and falls in love.

Returning home, he persuades his foreman Joe, an incorrigible womanizer, to write her a letter in Tony's name.

Years later, in 1956, Frank Loesser turned the play into the semi-operatic musical The Most Happy Fella.