An imaging lens assembly includes five lens elements with refractive power, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. The first lens element with positive refractive power has a convex object-side surface. The second lens element has positive refractive power. The third lens element has refractive power. The fourth lens element with refractive power has a concave image-side surface, wherein both of an object-side surface and the image-side surface of the fourth lens element are aspheric. The fifth lens element with refractive power has a concave image-side surface, wherein at least one inflection point is formed on the image-side surface of the fifth lens element, and both of an object-side surface and the image-side surface of the fifth lens element are aspheric.