In enzymology, a methionyl-tRNA formyltransferase (EC 2.1.2.9) is an enzyme that catalyzes the chemical reaction

10-formyltetrahydrofolate + L-methionyl-tRNA^fMet + H₂O ${\displaystyle \rightleftharpoons }$ tetrahydrofolate + N-formylmethionyl-tRNA^fMet

This enzyme belongs to the family of transferases that transfer one-carbon groups, specifically the hydroxymethyl-, formyl- and related transferases. The systematic name of this enzyme class is 10-formyltetrahydrofolate:L-methionyl-tRNA N-formyltransferase. This enzyme participates in three metabolic pathways: methionine metabolism, one carbon pool by folate, and aminoacyl-tRNA biosynthesis.

As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 1FMT and 2FMT.