A photographing lens assembly includes, in order from an object side to an image side: a first, a second, a third, a fourth, a fifth and a sixth lens elements. The first lens element with negative refractive power has an object-side surface being concave in a paraxial region thereof, wherein the object-side surface has at least one convex critical point in an off-axis region thereof. The third lens element has an image-side surface being convex in a paraxial region thereof. The fourth lens element has positive refractive power. The fifth lens element with negative refractive power has an object-side surface being concave in a paraxial region thereof, and an image-side surface being convex in a paraxial region thereof. The sixth lens element has an image-side surface being concave in a paraxial region thereof, wherein the image-side surface has at least one convex critical point in an off-axis region thereof.