Technophobia's clients include the Co-Operative Bank, Pizza Express and the Technology Strategy Board.
Capita is hoping that the acquisition will further enhance its web-based information management solutions, such as web sites, intranets, and extranets for public and private sector customers.
Capita aims to let Technophobia remain a standalone entity, even though it will be part of its IT services division.
"Technophobia has bucked the trend by growing significantly despite the challenging market conditions, so it's an exciting acquisition for us," said Paul Dawson.
"Competition is tougher than ever for the private sector and having a web site that is easy to navigate, intuitive and integrates neatly with other channels of communication – be that internal or external – is essential," he added.
"For the public sector the trend is to move services online, enable self service and engage citizens in new ways. Together, we are in a great position to support our customers and help them to future-proof for the next wave of demands."
Technophobia's turnover has increased by 81 per cent in the past two years.