<p>Ring-opening metathesis polymerization (ROMP) of cyclic olefins has been widely used in the synthesis of advanced polymeric materials. Control of the <i>cis</i>-/<i>trans</i>- (<i>Z</i>-/<i>E</i>-) olefinic double bonds in the resulting ring-opened polymers is important for the design of functional polymers, especially in controlling their morphology. This minireview introduces the basics of olefin metathesis reactions, especially ROMP, and summarizes reported examples of stereocontrol in ROMP through the use of ruthenium-carbene, molybdenum-alkylidene, vanadium-alkylidene, and niobium-alkylidene catalysts. The efforts have been applied to the <i>cis</i>-/<i>trans</i>-specific synthesis of bottlebrush polymers, enabled by the use of (arylimido)vanadium(V)-alkylidene catalysts that exhibit different thermal and emission properties because of their different morphologies [as confirmed by atomic force microscope (AFM)] and interpolymer and/or intrapolymer interactions.</p>