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.

At the age of 32, Eames is the youngest full-time boss in the top four divisions of English football.
"We support his playing style and our team responds positively to his philosophy," chairman Tony Kleanthous told the club's official website.
Meanwhile, defender Bira Dembele, 29, and midfielder Tom Champion, 31, have left the League Two club.
Dembele played 57 times having joined Barnet in 2015, while Champion scored once in 32 appearances last season.
Eames took joint charge of the Bees in December when Martin Allen left to join Eastleigh, winning four of his 11 games alongside Henry Newman.
He then won two of the final four games of the season after Kevin Nugent was sacked as head coach in April.
Eames was previously a coach with the club's development and academy sides before working as Nugent's assistant.
"For us this was the bold choice and the right time to finally allow Rossi to take sole control of our football destiny," said Kleanthous.
Barnet finished 15th in League Two this season, 11 points above the relegation zone.
A large crowd has gathered in Glasgow's George Square for a pro-independence rally one year after the referendum.
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Barnet have appointed former interim manager and assistant first team coach Rossi Eames as their new head coach.