Sidebar is a term for information placed at one or both sides of an article in a printed or Web publication, graphically separate from the rest of the display but with some contextual connection. Graphically separate information which is not connected, such as a different article or a table of contents, is not considered a sidebar.

The term has long been used in newspaper and magazine layout. It is now common in Web design, where sidebars originated as advertising space and have evolved to contain more useful information such as quick links to other parts of the site, or links to related materials on other sites.

Sidebar often include small bits of information such as quotes, polls, lists, pictures, site tools, etc.