Events took place in various cities yesterday to show solidarity and support for LGBT (lesbian, gay, bisexual and transgender) people worldwide.
Soho, the heart of London's gay district, was packed with people who held a two-minute silence and hundreds also gathered in Glasgow's George Square to pay their respects.
"We're from Free Pride which is an LGBT community group in Glasgow and we just felt we needed a place where people could come and be around friends, and show solidarity with the people in Orlando as well," Organiser Ciara McGuire told BBC.
Prince William and his wife Kate Middleton paid a visit to the US embassy in London today to sign the book of condolence in memory of the victims.
More From This Section
They were greeted by the US Ambassador and also met with a small group of US Embassy staff after paying tribute.
As a mark of respect Kate wore a knee-length black and white dress teamed with a cropped black blazer.
Prime Minister David Cameron had tweeted his condolences: "I'm horrified by reports of the overnight shooting in Orlando. My thoughts are with the victims and their families."
Vigils were also held in Birmingham, Manchester, Cardiff, Brighton, Leeds and Nottingham, with more planned in the coming weeks.
US authorities have confirmed that gunman Omar Mateen had pledged allegiance to the Islamic State (ISIS) terrorist group before he went on his rampage at Pulse nightclub in Orlando.
Scotland Yard said, "On Saturday, 25 June, Pride in London hold their annual parade and related events in central London for the Lesbian, Gay, Bisexual and Transgender community.
"The Metropolitan Police Service has a current robust, visible policing plan in place and are working closely with event organisers to reassure those planning to attend. There are a number of contingencies in place that will be reviewed as we approach the event.