Afflick will be responsible for helping the organisation deliver London’s third-largest annual event.
He had previously held the role of deputy director in the communications team, and his promotion follows several rounds of interviews alongside external candidates.
He replaces Asad Dhunna, who has stepped back to focus on his new agency The Unmistakables.
Afflick will oversee the organisation’s comms strategy spanning PR, international communications, social media, content and political engagement.
He will also work closely with the marketing team on Pride in London’s annual theme and creative campaign.
Afflick said he was extremely proud to be leading the team.
"With this year’s Pride Jubilee still fresh in our minds, it’s more important than ever for our communications to reflect the extraordinary and wonderful diversity of London and its LGBT+ communities - especially groups that are often under-represented," he added.
Pride in London engaged over 40.7 million people via its social channels this year and reached one in three people in the UK through its PR and influencer coverage.
Pride in London co-chair Alison Camps said: "I have no doubt that Rhammel’s expertise in communications will help us spread our messages of equality, diversity and protest throughout the press, social media and the government.
"I’d also like to take this opportunity to thank Asad Dhunna for his service and look forward to seeing him at Pride in London events in the future."