While Jupiter is the most massive planet, Saturn's rings make it the widest, with a diameter of about 120,536 kilometers (74,898 miles). This includes the extent of its rings.

Without the rings, Saturn's diameter is still larger than Jupiter's at 120,536 kilometers (74,898 miles) compared to Jupiter's 142,984 kilometers (88,846 miles).

However, it's important to note that when comparing planetary diameters, it's usually referring to the diameter of the planet itself, not including any rings.