A zoom lens system includes, from the object-side to the image-side thereof, a first lens group, a second lens group, and a third lens group. The first lens group includes a first lens and a second lens. The second lens includes a third lens, a fourth lens, and a fifth lens. The fourth lens and the fifth lens are attached to each other. The third lens group includes a sixth lens. The zoom lens system satisfies the following conditions: 0.35