An imaging lens assembly includes, 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, a fifth lens element, and a sixth lens element. The first lens element has refractive power. The second lens element has refractive power. The third lens element has positive refractive power. The fourth lens element has negative refractive power. The fifth lens element with refractive power has an image-side surface being concave in a paraxial region thereof. The sixth lens element with refractive power has an image-side surface being concave in a paraxial region thereof, wherein the image-side surface of the sixth lens element has at least one convex shape in an off-axis region thereof. The imaging lens assembly has a total of six lens elements with refractive power.