Clifton K. Hillegass (18 April 1918, Rising City, Nebraska – 5 May 2001, Lincoln, Nebraska) was the creator and publisher of CliffsNotes.

CliffsNotes are literary study guides in their familiar black and yellow covers that assist college and high school students in their literature course work. There are currently about 300 titles available in 7,000 retail outlets.

Clifton Hillegass graduated from Midland Lutheran College.