A bicycle battery holder for retaining a battery is basically provided with a bracket member, an engaging member and a lever member. The engaging member is movably mounted to the bracket member and configured to selectively retain the battery to the bracket. The lever member is movably mounted to the bracket member and operatively coupled to the engaging member to move the engaging member in a first direction with respect to the bracket member when the lever member is moved from a first lever position to a second lever position.