About 200 people attended the event in St Enoch Square, part of the worldwide Bring Back Our Girls campaign.
Security forces are still searching for the students, who were abducted by Boko Haram Islamist militants on April 14.
Josephine Adekola, a representative of the Nigerian community in Glasgow, said: "Every Nigerian across the world, wherever they are, feels frustration and anger about this.There's real concern and anxiety about Boko Haram."
Event organiser Megan Mitchell said: "We won't be silent. We're a month down the line from these girls going missing and there's been inaction from governments, charities, the media and international community."
Foreign news: page 38