"Didn't I (Blow Your Mind This Time)" is a song by American soul group the Delfonics, co-written by producer Thom Bell and lead singer William Hart.

A prominent example of the Philadelphia soul style, "Didn't I" is a slow ballad, with layered strings and horns and highly chromatic harmony.

A version by boy band New Kids on the Block, slightly re-titled "Didn't I (Blow Your Mind)", was featured on the group's 1986 self-titled debut album.

Their version was later released as a single in 1989 in an attempt to boost sales of its parent album in light of the group's subsequent success.

The song has been extensively covered since 1970, by artists included Aretha Franklin (from Young, Gifted and Black in 1971), brothers David and Jimmy Ruffin, Spinners (from Can't Shake This Feeling in 1981), Lisa Fischer, Regina Belle, Jackie Jackson, the Trammps, Maxine Nightingale and Patti LaBelle.