Abstract: A child-resistant cap for containers is provided. The child-resistant cap includes an outer cap and an inner cap. The outer cap is configured with a knurled side wall and includes a plurality of inner projections and a plurality of involute teeth projected on an inner top surface. The inner cap is configured to fit into the outer cap and includes an inner side wall which includes a plurality of ribs positioned on the outer side. The space between the adjacent ribs of the plurality of ribs includes an inclined structure and a plurality of undercuts. An outer top surface of the inner cap includes a plurality of projections with a wedge-shaped structure which is configured to mesh with the plurality of involute teeth. The wedge-shaped structure includes a chamfered edge. A bottom surface of the inner cap is configured as a tapered surface.