It's a Bikini World (1967)

Male chauvinist Mike attempts to get an intelligent burgeoning feminist Delilah into his harem. When she resists, Mike then poses as his brother Herbert, but in the process falls in love with Delilah.

Directed by: Stephanie Rothman

Starring: Deborah Walley, Tommy Kirk, Bobby Pickett, Suzie Kaye, Jack Bernardi, William O'Connell

Links: IMDb, Movie posters, Movie stills