Lithium‐doped ZnSe has been grown on (100) GaAs by molecular beam epitaxy. The epitaxial layers arep‐type with net acceptor concentrations (NA−ND) as high as 8×1016cm−3— the highest ever reported for molecular beam epitaxial ZnSe. Room temperature ac measurements show resistivities as low as 2.9 &OHgr; cm. Higher Li concentrations give rise to self‐compensation and a decrease inNA−ND. The details of the electrical and optical characterization of these layers are presented. Rudimentary blue light emittingpnjunction diodes have been fabricated. While these devices show dominant blue emission (463 nm) at room temperature, large turn‐on voltages indicate that thep‐ZnSe/p‐GaAs interface presents a large barrier to hole transport. Moreover, we find that difficulty in making device‐quality ohmic contacts top‐ZnSe is the next major obstacle to the fabrication of efficient blue light emitting diodes.