Lewis Merenstein (born October 23, 1934, Baltimore, Maryland, USA – died September 6, 2016, New York City, New York, USA) was an American record producer. He is perhaps best remembered as the producer of Van Morrison - Astral Weeks and the executive producer of Van Morrison - Moondance.

Formed production / management company Schwaid-Merenstein and Schwaid, Merenstein & Thau, Inc. with Bob Schwaid and Marty Thau.
His aunt was Bessie (Merenstein) Berman, co-founder of Apollo Records); and his uncle was Charles Merenstein, a co-writer of the song Handy Man.