The sun3x architecture was Sun Microsystems' final family of m68k-based workstations. The sun3x systems were based on the m68030 microprocessor (as opposed to the m68020 used in the sun3) and used the 030's native MMU. The family also borrows from the sun4 family of systems which were developed at the same time.

The sun3x family includes the Sun 3/80 and the Sun 3/4xx workstations.