It was declared early on Friday morning that Ms Olney will secured the seat after receiving 34,559 votes.
The Conservative candidate, Zac Goldsmith, came in at second place on election night, losing his seat with 26,793 votes.
She was followed by Labour’s Sandra Keen in third place with 3,407 votes, while independent Caroline Shah received 247 votes and independent candidate John Usher secured 61 votes.
The seat was held by Goldsmith between 2010 and 2015 until Sarah Olney claimed it in a 2016 by-election. But Mr Goldsmith had fought back to claim the seat back the next year in 2017, but with a majority of just 45.
The turnout was very high again this year at 78.7 per cent