MEST or Mest may refer to:
As an initialism:

• Middle European Summer Time, obsolete variant name of the Central European Summer Time, a time offset
• MEST (Scientology) ("Matter, Energy, Space and Time"), used in Scientology to refer to the physical universe
• MEST (gene), a gene in humans that encodes the mesoderm-specific transcript homolog protein
• Meltwater Entrepreneurial School of Technology, a school in Accra, Ghana
• Cystic nephroma, a type of begin kidney tumor also known as a mixed epithelial stromal tumor
• Message Exchange State Transfer, a protocol in service-oriented architecture

Mest is a pop punk band from Blue Island, Illinois. The band's lineup, prior to their breakup in 2006, consisted of vocalist and guitarist Tony Lovato, guitarist Jeremiah Rangel, bassist Matt Lovato, and drummer Nick Gigler. They broke up in 2006 after an eleven year run, but reformed in 2008 with a new lineup, featuring only their singer returning for a final tour for people who missed the last one.