"Girlguiding UK has increasingly found the introduction of branded goods highly popular with its younger members and this new partnership signifies the charity's continuing development of its successful CRM strategy," said a statement from Girlguiding UK.
CRM stands for customer relationship marketing.
Girlguiding UK's existing branded gift range includes Brownie Pyjamas, Rainbow dolls and its Kit Heath silver jewellery.
As well as bikes, Girlguidng UK is planning to market Brownie and Rainbow helmets and water bottles.
Paul Easton, Girlguiding UK's marketing & promotions manager, said:
"Health and fitness is an important part of the girl's activity programmes and the bikes fit perfectly into these sporting activities. The partnership with Raleigh means that we benefit from their respected and trusted identity and Raleigh benefit from the strong brand identities of Brownies and Rainbows."
Paul Chapman, Raleigh's direct marketing co-ordinator, said:
"We are always looking for new and exciting designs to portray on our bikes. Rainbows and Brownies are synonymous with girls having fun and enjoying themselves, so joining together with Girlguiding UK to create these exclusive bikes was the perfect addition to our girls range."
There are no details on the Girlguiding UK website of how the bikes - to ship in December - will arrive at consumer's doors. 'Bikes in boxes', sold mail order, is always a topic of contention with the Association of Cycle Traders.
Rainbows and Brownies are the youngest members of Girlguiding UK. Rainbows are aged 5-7 years and Brownies are 7-10 years. They account for over half of the membership of Girlguiding UK with nearly 350 000 girls between them.