The Hardy Boys/Nancy Drew Mysteries (re-titled The Hardy Boys for season three) is an American television mystery series based on the Hardy Boys and Nancy Drew juvenile novels. The series, which ran from January 30, 1977, to January 14, 1979, was produced by Glen A. Larson from Universal Television for ABC. Parker Stevenson and Shaun Cassidy starred as amateur detective brothers Frank and Joe Hardy, respectively, while Pamela Sue Martin (later Janet Louise Johnson) starred as amateur sleuth Nancy Drew.

The Hardy Boys/Nancy Drew Mysteries was unusual in that it often dealt with the characters individually; the series alternated between episodes that featured the Hardys and episodes featuring Drew in its first season. As the series progressed, the two storylines crossed over, and the Nancy Drew character was drastically reduced, and then dropped, in favor of the Hardys.