A knob assembly includes a front panel, a knob located at a front side of the front panel and configured to rotate based on operation by a user, a knob shaft that is coupled to the knob and that extends through the front panel, a supporting pipe that receives the knob shaft and that supports the knob shaft, the supporting pipe being configured to maintain a position relative to the front panel, a valve configured to control supply of gas to the appliance, a valve shaft connected to the valve and configured to control the valve to adjust a flow rate of gas based on rotation of the valve shaft, and a joint that couples the knob shaft to the valve shaft and that is configured to transfer at least one of a rotational motion or a linear motion of the knob shaft to the valve shaft.