We study the semitopologization functor of Friedlander and Walker from the perspective of motivic homotopy theory. We construct a triangulated endofunctor on the stable motivic homotopy category SH(C), which we call homotopy semitopologization. As applications, we discuss the representability of several semitopological cohomology theories in SH(C), a construction of a semitopological analogue of algebraic cobordism and a construction of Atiyah-Hirzebruch type spectral sequences for this theory.