In comparison with the well‐researched lateral and local buckling that takes place in bare steel beams, the buckling that takes place in composite steel‐concrete beams is far more complex, and is still a grey area in structural mechanics. Plastic design of continuous composite beams is very advantageous, but this can only be achieved if buckling is prevented. This article reviews the research to date into local and lateral‐distortional buckling in the negative moment region of continuous composite beams, and provides design proposals. It is concluded that there is still a need for focused research into the buckling phenomenon if full advantage is to be taken of moment redistribution in plastic design.