Stephen E. Cosgrove (born July 26, 1945) is a children's author and toy designer.

In 1978, after selling over 3 million books,[citation needed] Cosgrove sold Serendipity Press to Penguin/Putnam and began focusing on multimedia literature for children.

In 1990, Cosgrove and Wendy Edelson were awarded the Silver Jubilee Honor by the Pacific Northwest Booksellers Association (PNBA) for "Ira Woodworthy".

[citation needed] In 2002, Cosgrove created the websites Web-pop, Book-pop, and Chatty Hattie, where children can read stories online with colorful and interactive illustrations.

Two years later, in 2004, he created the website BuggBooks, where children can have stories read to them by the author.