Ladders and ladder components are provided including feet for ladders configured for securement of the ladder to a supporting surface, adjustable leg members for ladders, bearing members for ladders, and adjustment mechanisms for ladders. In one embodiment, an adjustment mechanism may include a first pair of spaced apart rails, a pair of adjustable legs having a first end hingedly coupled to one of a pair of adjustment mechanisms and a second end coupled with a foot. The adjustment mechanisms may be slidably coupled with the rails and in one embodiment, each adjustment mechanism is selectively displaceable along a length of its associated rail only when upward force is absent from the adjustment mechanism, the upward force being defined in a direction from a lower end of the associated rail towards the adjustment mechanism.