The planet between Earth and Jupiter in order from the Sun is Mars.
The planetary sequence outward from the Sun is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Mars is therefore the fourth planet from the Sun and the outer neighbor of Earth, while Jupiter is the next planet beyond it.
Mars is often called the Red Planet because iron minerals in its surface rocks oxidize, or rust, and give the dust a reddish appearance. It is smaller than Earth and has two tiny moons, Phobos and Deimos. A common mix-up is placing Venus between Earth and Jupiter; Venus is actually Earth’s inner planetary neighbor, closer to the Sun.