A bicycle crank axle assembly has first and second crank arms that are attached to opposite ends of a crank axle. The ends of the crank axle are non-rotatably disposed in axle mounting openings of the first and second crank arms. A first end of the crank axle has at least one axially extending first spline that protrudes radially outward from an outer peripheral surface of its middle body portion. The at least one axially extending first spline non-rotatably couples the crank axle to the first crank arm and prevents outward axial movement of the first crank arm away from the second crank arm. The second end portion of the crank axle has at least one recess that extend radially inward with respect to the outer peripheral surface of the middle body portion to form at least one axially extending second spline.