Gundotra revealed he was leaving the company on a post on his Google+ page, which was headlined "and then..." and paid tribute to the work carried out by his team in the face of many critics.
He said: "I'm overwhelmed when I think about the leadership of Larry Page and what he empowered me to do while at Google. From starting Google I/O, to being responsible for all mobile applications, to creating Google+, none of this would have happened without Larry's encouragement and support.
"I'm also forever in debt to the Google+ team. This is a group of people who built social at Google against the scepticism [sic] of so many.
"The growth of active users is staggering, and speaks to the work of this team. But it doesn't tell you what kind of people they are. They are invincible dreamers. I love them. And I will miss them dearly."
The growth of Google+ users has been criticised by many because of the way Google has effectively forced people to sign up by methods including making changes to YouTube that means users can only comment on videos if they have a Google+ account.
Marvin Chow, the Google+ marketing chief, paid tribute to Gundotra by thanking him for how much he learnt from him on both a personal and a professional level.
It is reported that Google+ will no longer be seen internally as a standalone product that competes with Facebook and Twitter, but instead will be now treated as a platform with Google restructuring the team accordingly.
Google+ VP of engineering David Besbris will reportedly replace Gundotra ahead of Gundotra’s right hand man, Google+ product chief Bradley Horowitz.
It is rumoured Gundotra is already interviewing for other jobs on a post that appeared a few days ago on the Secret.ly app, which is an anonymous social network for tech insiders.