Scores were pictured waving union jacks and singing patriotic songs. A separate protest in Glasgow was held against the UK’s EU exit on Buchanan Street.
According to Heart Scotland News one Brexit supporter was detained by police after an altercation with remainers.
A majority of Scots voted remain in 2016, but a significant minority did back Brexit.
In last year’s European Parliament elections the Brexit Party secured one of Scotland’s six MEPs.
Speaking to Heart Scotland News one Brexiteer in George Square commented: “I’m so happy it’s been a long time coming.”
Brexit supporters gather in Glasgow (Image: Heart Scotland News)
Brexit was celebrated in Glasgow's George Square (Image: GETTY)
Hundreds of anti-Brexit protestors also gathered in Edinburgh where they were addressed by SNP politicians.
The moment Brexit took place was marked in Glasgow’s George Square by cheering, the throwing of confetti and waving of union jack flags.
Separately many thousands gathered to celebrate Brexit in London’s Parliament Square.
The rally, organised by Leave Means Leave, was addressed by Brexit Party leader Nigel Farage.
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Brexiteers in Glasgow's George Square (Image: Heart Scotland News)
Mr Farage said: “The fact is