All planets in our Solar System spin from west to east. But only Venus spins in other way round. 
Venus is about the same size as the Earth, but it is located closer to the Sun star. It moves slowly from east to west.
Surprisingly, but its day is much longer than its year. When the Earth takes twenty four hours to have a full circle, Venus takes 243 of our days!venus-rottaion
But it moves a bit faster than the Earth around the Sun. Venus needs less than 255 days to have a complete trip around our star.
Since Venus is shrouded in dense clouds, it is quite hard to estimate its rotation rate by observing it through a telescope.
There are some theory proposed to explain its retrograde movement. One theory proposes that 4600 millions years ago, Venus collided with another young planet and its spinning then reversed.
The puzzle of why Venus rotates backwards is still mysterious. There is still no concrete answer to that mystery… only theories…