The campaign was designed to "help make reading fun" and has "smashed" its original target to distribute 15 million books by the end of 2014, said a spokesperson for the fast food chain.
The campaign launched in January 2013, in partnership with the National Literary Trust, WHSmith and Kobo, in response to research that showed one third of children did not own a book and half did not enjoy reading.
As part of the ‘Happy Readers’ incentive, McDonalds’s gives away vouchers and £1 deal offers that can be exchanged for fiction and non-fiction books, including paper and as e-book classics by Enid Blyton.
Alistair Macrow, McDonald's senior vice president of marketing, said: "Our restaurants have always been a colourful and exciting place for families to visit, and two years ago we realised we could leverage our scale, our partnerships and our presence in communities across the country to help millions of mums, dads and children find the fun in reading."
"Reading is something families continue to love doing together, and Happy Readers has really struck a chord. I’m delighted we’ve been able to put more than 22 million books into the hands of families around the UK.
"It’s a fantastic achievement and something we will remain committed to in the future."