Allen Holub’s Quick UML reference. Lots of examples to help you understand each notation element, including code examples of how some aspects would be expressed in Java for those with a programming background that may find this “mapping” useful to understand the concepts.All UML2 diagrams covered, with some basic explanations for the main notation elements.

There are no explanations, so it’s more of a notation reminder. It covers all diagrams, some in more detail than others. UML reference sheet from the National University of Singapore.Very simple but I include it as I like the minimal “semantic” description regarding association cardinalities and the distinction between composition and aggregation. UML Notation summary for class diagrams and sequence diagrams.It used to have also some UML self-tests but they don’t seem to be working anymore Embarcadero’s Practical UML guide: Complete coverage of all diagrams.

It is updated to reflect the UML 2.5 version. It’s more a reference guide than a cheat sheet though, since each diagram has its own dedicated page.

UML Diagrams: Detailed overview of all UML diagrams (including the new features of the latest UML versions).

Another 1-page quick reference, great to be printed and keep close to you. Class, use case and sequence diagrams covered Example diagrams are annotated with the name of the modeling elements used in the example.

If you need a quick reference guide for the UML notation, check one of the following great UML cheat sheets (in no particular order, though the last one if my preferred one):

Sequence diagram online tool uml 2.5