The Salisbury Convention is a constitutional convention in the United Kingdom that means that the House of Lords will not oppose any government legislation promised by its election manifesto.

It was introduced by Lord Salisbury, the Conservative leader of the House of Lords, following a landslide Labour general election victory in 1945. Salisbury believed that because Clement Attlee's Labour government had a clear mandate to deliver the policies of nationalisation and welfare state measures, the House of Lords should not oppose such legislation at the second reading.