Organisers said they intended the Hope over Fear rally to send a message that the journey to Scottish independence continued.
The city of Glasgow voted in favour of independence at last year's ballot.
Hope over Fear said it is an apolitical organisation, which evolved from Solidarity co-convener Tommy Sheridan's referendum campaign speaking tour.
Twenty-eight speakers were to address the all-day gathering and organisers said thousands of people were expected at "Freedom Square".
Police estimated the crowd at about 1,500 at its peak. They said there had been no issues and no arrests.
Mr Sheridan told BBC Scotland: "We are very pleased that the Yes family is here in Glasgow again to say loud and clear, one year on, not only are we still Yes but more of us are Yes."
The former socialist MSP said independence was "no longer a question of if but a question of when" and he called the No campaign's success in the referendum on 18 September last year a Pyrrhic victory.
"They won a battle but they have lost the war for the hearts and minds of the people of Scotland," he said.
"Scotland is now a Yes country and the next referendum will prove that."
Mr Sheridan said a second referendum must be held by 2018 at the latest.
A large crowd has gathered in Glasgow's George Square for a pro-independence rally one year after the referendum.