LAME is an MPEG-1 audio layer 3 (MP3) encoder. The name LAME is a recursive acronym for LAME Ain't an MP3 Encoder, reflecting LAME's early history when it was not yet a complete encoder in itself.

At one time, LAME was simply a set of patches against the separately distributed ISO demonstration source, hence the claim that it "ain't an encoder". The ISO code had a restrictive license but was available without charge. In May 2000, the LAME project reimplemented the last of the ISO source code, and thus LAME was then a totally new implementation