An imaging lens assembly, including, in order from an object side to an image side: a first lens element having negative refractive power; a second lens element with positive refractive power having an image-side surface being convex; a third lens element, a fourth lens element with positive refractive power having an object-side surface being concave and an image-side surface being convex; a fifth lens element with negative refractive power having an image-side surface being concave, at least one convex shape on the image-side surface in an off-axial region, and both of object-side and image-side surfaces thereof being aspheric; wherein the imaging lens assembly has a total of five lens elements.