The petition was launched at 11am on Thursday, after STV announced plans to exclude the Scottish Greens despite the party's strong polling and surge in membership.
The leaders of Scotland's four other main parties backed the call for STV to invite the Greens.
Handing in the petition at STV's HQ in Glasgow today, Zara Kitson, Scottish Green MP candidate for Glasgow North-east, said:
“The huge support we've had from across Scotland, and across the political spectrum, shows that a broadcaster excluding the Scottish Greens is out of touch with its audience. TV debates remain an important part of our democracy, and as we head towards an election like no other with an electorate more engaged than ever before, it's essential that voters get to hear a broad range of voices.
"The option of legal action remains open to us but we hope today's show of support prompts a rethink by STV."