The Children's Encyclopedia was a printed encyclopedia in ten volumes, originated by Arthur Mee, and published by the Educational Book Company Ltd. of London, England. It was published from around 1910 through to the early 1960s, and was found in many family homes throughout the British Empire.

The format of the encyclopedia was unusual, in that it could be used as a conventional reference library, or read from start to finish, developing its various topics as it progressed. It could also be dipped into at random to provide entertainment and reading matter whenever required. As well as factual articles, it contained many classic stories, nursery rhymes, songs, bible stories and poems.

The encyclopedia was organised into the following sections:

  • Earth and its neighbours
  • Men and women
  • Stories
  • Animal life
  • History
  • Familiar things
  • Wonder
  • Art
  • Ourselves
  • Plant life
  • Countries
  • Picture atlas
  • Poetry and nursery rhymes
  • Powers
  • Literature
  • Ideas
  • The Bible
  • Things to make and do
  • School lessons

The tenth volume contained a traditional index so that the encyclopedia could be used as a standard reference work.

The tone of the encyclopedia was thoroughly didactic, written with an often far from neutral point of view. Articles reflected the often strong and occasionally controversial views of its editors and contributors, including religious views, eugenics, and blatant sexism and occasional offhand racism. Offsetting this was a moderate and liberal standpoint in many areas.

While The Children's Encyclopedia was never sold in the United States, it was re-edited for the US market and retitled The Book of Knowledge. A new company, Grolier, was founded to publish and distribute the book.

The encyclopedia was sold door-to-door, and many families bought it wishing to better themselves and their children. It was also used extensively by schools and for teacher training. As such the book is widely recognised as being very influential for several generations of British and Commonwealth children, and has become the subject of study by social historians, as it gives a great insight into the social values of the society that created it, and which in turn was influenced by it.

The encyclopedia began as a serialised article in The Children's Newspaper, which was editied by Mee, and the series was first published in March, 1908. In 1910 publishing was taken over by The Eduactional Book Company, and released as an 8-volume set. There were 12 editions of the 8-volume set, which was then expanded to the ten volume set in 1923. A further 14 editions in this form were published, ending in 1946. A post-war edition was published in the 1950s and 60s.