Dia (/ˈdiːə/)[3] is free and open source general-purpose diagramming software, developed originally by Alexander Larsson.

[1] It uses a controlled single document interface (SDI) similar to GIMP and Inkscape.

Dia has special objects to help draw entity-relationship models, Unified Modeling Language (UML) diagrams, flowcharts, network diagrams, and simple electrical circuits.

It can print large diagrams spanning multiple pages[4] and can also be scripted using the Python programming language.

Dia is currently maintained by Hans Breuer, Steffen Macke and Sameer Sahasrabuddhe.