The creative agency won the account after a pitch against Kitcatt Nohr Digitas. The review began in December and was run by Oystercatchers.
The business was previously handled by Flourish, while Enable Interactive oversaw part of Scope's digital work.
Meteorite will aim to help Scope increase income from individual givers and takes on responsibility for all fundraising supporter acquisition and retention activity.
The work will encompass CRM and eCRM, including all appeals activity, campaigns to regular givers and a new national supporter acquisition campaign.
Jason Suckley, the director of fundraising at Scope, said: "We weren't just impressed with the depth of Meteorite's thinking and ingenuity of their creative. We were impressed with them as people who clearly care about making a difference."