LEA (pronounced "lee-ah") is a fully featured macro assembler which can be used to turn assembly language programs into machine code ready to run on a target computer system. It was designed to be extensible and can assemble programs for more than one target CPU. The current version is able to assemble programs written for the following two target CPUs:

- Motorola 68000: This CPU is automatically selected if the file extension is 68K or X68.

- LEO-1: This CPU is automatically selected if the file extension is LEA.