Here shows the websites offering open textbooks at primary and secondary levels. You may choose the websites based on the disciplines they purposed for. Here is a chart helps you to source open textbooks from these websites:
| Icon | Meaning |
 | Many resources of the designated category are available |
 | Some resources of the designated category are available |
 | No resource is available in the designated category |
The table below is for reference only. The availability of resources in these websites may subject to change.
| Websites for open textbooks at primary and secondary levels | Discipline | ||
| Arts | Business | Science | |
| CK-12 http://www.ck12.org/student/ | | | |
| Curriki http://www.curriki.org/ | | | |
| California Free Digital Textbooks Initiative http://www.clrn.org/fdti | | | |
(as at 30 July, 2013)