A zoom lens system, in which chromatic aberration, spherical aberration, and coma may be excellently corrected in a balanced manner so as to obtain excellent optical performance over an entire zoom range, includes, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; and a rear lens group including a lens unit having a positive refractive power, in which: at least one of the first lens unit and the second lens unit is moved for zooming so that an interval therebetween at a telephoto end is larger than an interval at a wide angle end; the first lens unit includes at least one negative lens; and an Abbe number (νd1n) and a partial dispersion ratio (θgF1n) of a material of the at least one negative lens are appropriately set.