  We present nontrivial examples of d=3 gauge theories with sixteen and eight
supercharges which are infrared dual at special points in the moduli space.
This duality is distinct from mirror symmetry. To demonstrate duality we
construct the gauge theories of interest using D2-branes and orientifolds and
then consider their lift to M-theory. We also discuss the strong coupling limit
of orientifold two-planes and orbifolds of orientifold six-planes.
