There are a total of eight planets in our solar system. Closest to the sun is the planet Mercury then Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. There is an awesome mnemonic device to remember what order the planets are in: My Very Excellent Mother Just Served Us Nougat.
My = Mercury
Very = Venus
Excellent = Earth
Mother = Mars
Just = Jupiter
Served = Saturn
Us = Uranus
Nougat = Neptune
There are other mnemonic devices out there as well but this is usually the easiest to remember.