The twin-block appliance, described by Dr. Clark in the year 1977, is frequently used functional appliance. Contemporary studies suggest that, in growing patients, skeletal Class II malocclusion can be treated with this appliance. During the active phase, it guides molar eruption, and helps in reduction of posterior open bite by eruption of buccal teeth into occlusion. After which, an anterior inclined bite plane is used to maintain corrected occlusion. This is a case report of growing skeletal Class II patient who was successfully treated by twin block appliance.