"Ain't No Mountain High Enough" is a song written by Nickolas Ashford & Valerie Simpson in 1966 for the Tamla label, a division of Motown. The composition was first successful as a 1967 hit single recorded by Marvin Gaye and Tammi Terrell, and became a hit again in 1970 when recorded by former Supremes frontwoman Diana Ross. The song became Ross's first solo number-one hit on the Billboard Hot 100 chart and was nominated for the Grammy Award for Best Female Pop Vocal Performance.

Ashford & Simpson were an American husband-and-wife songwriting, production, recording duo composed of Nickolas Ashford and Valerie Simpson.