A lens assembly includes a lens barrel, a plurality of lenses and at least one light-shielding member. The lens barrel extends along an axis and includes a peripheral wall that surrounds the axis and defines a receiving chamber. The peripheral wall has open and aperture-forming ends that are opposite to each other and respectively adjacent to image and object sides of the lens assembly. The lenses are disposed in the receiving chamber in sequence along the axis between the aperture-forming and open ends. The light-shielding member is disposed in the receiving chamber and includes an annular light-shielding body and an adhesive layer for positioning the annular light-shielding body relative to at least one of the lenses.