The representative for Richmond Park balloted constituents to ask for their consent in joining the mayoralty fray.
Goldsmith secured the backing of 79% of those who replied, some 15,800 saying 'yes', with just 3,500, or 18%, saying 'no'.
He said in a statement to journalists: "I am hugely grateful to the residents of Richmond Park and North Kingston for taking part in the ballot, and am overwhelmed by the mandate they have given me to run for mayor.
"For five years I have campaigned hard on the issues that matter to my constituents, whether fighting to stop Heathrow expansion, pressing for free parking to help our small shops, stopping plans to charge people for enjoying Richmond Park, or campaigning to give voters more power over their MPs.
"I have seen how a campaigning MP can make a real difference."
The MP's victory will bolster Conservative hopefuls keen for Goldsmith to be chosen as the party's candidate for Mayor in 2016.
The keen environmentalist is widely-tipped to be the frontrunner in a hotly-contested Tory candidacy race.
He is so far ahead in the bookies' odds on declared competitors Sol Campbell, the former England footballer, Andrew Boff, leader of the Conservative Group on the London Assembly, and Ivan Massow, a financial services entrepreneur, among others.
Goldsmith has held his seat for five years having ousted Liberal Democrat MP Susan Kramer in 2010.
In the May 2015 General Election he increased his majority by 8.5%.