Open source UML tools for Windows

BOUML

BOUML is a free UML 2 tool box allowing you to specify and generate code in C++, Java, Idl, Php and Python. (GPL)

Linux - FreeBSD - Windows - MAC OS X

Gaphor

Gaphor is a UML, SysML, RAAML, and C4 modeling application written in Python. It is designed to be easy to use, while still being powerful. Gaphor implements a fully-compliant UML 2 data model, so it is much more than a picture drawing tool. You can use Gaphor to quickly visualize different aspects of a system as well as create complete, highly complex models. (Apache)

Linux - Windows - MAC OS X

Modelio

Modelio is an open source modeling environment. Modelio delivers a broad-focused range of standards-based functionalities for software developers, analysts, designers, business architects and system architects. (GPL)

Cross-platform

Papyrus

Papyrus is aiming at providing an integrated and user-consumable environment for editing any kind of EMF model and particularly supporting UML and related modeling languages such as SysML and MARTE. (EPL)

Cross-platform

UML Designer

UML Designer provides a set of common diagrams to work with UML 2.5 models. The intent is to provide an easy way to make the transition from UML to domain specific modeling. (EPL)

Cross-platform

Umple

Umple is technology for Model-Oriented Programming. It adds abstractions such as UML associations, attributes, and state machines to object-oriented programming languages such as Java, PHP and Ruby. (MIT)

Cross-platform

6 applications