Mary Esther Wells (May 13, 1943–July 26, 1992) was an American soul and R&B singer. She was one of the signature voices of the Motown sound. Wells auditioned for Tamla Records in 1961, and Berry Gordy immediately signed her to his Motown label. Wells remained with Motown until 1966.

Hers was the voice on the single "My Guy", which went to Number One in 1964. Though other R&B stylists have covered the song, Wells' version has endured as one of the most memorable hits of the early Motown years. Wells continued to sing through the early 1980s until she was diagnosed with cancer of the larynx. She died in July 1992.

Other hit records by Mary Wells:

• "Bye Bye Baby" (1961)
• "The One Who Really Loves You" (1962) - #8
• "You Beat Me to the Punch" (1962) - #9
• "Two Lovers" (1962) - #7
• "Once Upon a Time" (1964) - #17