An image capturing system comprising six lens elements (E1-E6), the six lens elements (E1-E6) being, in order from an object side to an image side along an optical path, 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, and each of the six lens elements (E1-E6) having an object-side surface facing toward the object side and an image-side surface facing toward the image side; wherein the fourth lens element has positive refractive power, the object-side surface of the fourth lens element is concave in a paraxial region thereof, the image-side surface of the fourth lens element is convex in a paraxial region thereof, the object-side surface of the sixth lens element is convex in a paraxial region thereof, the image-side surface of the sixth lens element is concave in a paraxial region thereof, and at least one of the object-side surface and the image-side surface of at least one lens element of the image capturing system has at least one inflection point in an off-axis region thereof; wherein an Abbe number of the fourth lens element is V4, an Abbe number of the fifth lens element is V5, a central thickness of the first lens element is CT1, a central thickness of the second lens element is CT2, a central thickness of the third lens element is CT3, a central thickness of the fourth lens element is CT4, an axial distance between the first lens element and the second lens element is T12, an axial distance between the third lens element and the fourth lens element is T34, and the following conditions are satisfied: 1.2 < V 4 / V 5 < 7.0; 3.5 < CT 1 + CT 2 / T 12 < 9.0; and CT 3 + CT 4 / T 34 < 6.5; wherein the image capturing system is characterized in that the image-side surface of the second lens element is convex in a paraxial region thereof, half of a maximum field of view of the image capturing system is HFOV, a curvature radius of the image-side surface of the second lens element is R4, and the following conditions are satisfied 52.0 degrees < HFOV < 80.0 degrees; and − 7.0 < R 4 / CT 2 < − 1.6. wherein the fourth lens element has positive refractive power, the object-side surface of the fourth lens element is concave in a paraxial region thereof, the image-side surface of the fourth lens element is convex in a paraxial region thereof, the object-side surface of the sixth lens element is convex in a paraxial region thereof, the image-side surface of the sixth lens element is concave in a paraxial region thereof, and at least one of the object-side surface and the image-side surface of at least one lens element of the image capturing system has at least one inflection point in an off-axis region thereof; wherein an Abbe number of the fourth lens element is V4, an Abbe number of the fifth lens element is V5, a central thickness of the first lens element is CT1, a central thickness of the second lens element is CT2, a central thickness of the third lens element is CT3, a central thickness of the fourth lens element is CT4, an axial distance between the first lens element and the second lens element is T12, an axial distance between the third lens element and the fourth lens element is T34, and the following conditions are satisfied: 1.2 < V 4 / V 5 < 7.0; 3.5 < CT 1 + CT 2 / T 12 < 9.0; and CT 3 + CT 4 / T 34 < 6.5; wherein the image capturing system is characterized in that the image-side surface of the second lens element is convex in a paraxial region thereof, half of a maximum field of view of the image capturing system is HFOV, a curvature radius of the image-side surface of the second lens element is R4, and the following conditions are satisfied 52.0 degrees < HFOV < 80.0 degrees; and − 7.0 < R 4 / CT 2 < − 1.6.