A cutting element for an earth-boring tool includes a substrate and a volume of superabrasive material disposed over the substrate. The volume of superabrasive material may include a cutting face and a longitudinal extension extending longitudinally along a lateral side surface of the substrate. An outer peripheral surface of the longitudinal extension may define at least a portion of a lateral side surface of the cutting element and may have a surface roughness less than about 10 μin. (about 0.254 μm) RMS. Earth-boring tools may include such cutting elements. Methods may include forming such cutting elements.