A hung parliament is a situation in which no single political party or pre-existing coalition has an absolute majority of legislators in a parliament or other legislative body. In the Westminster system, which is used in many countries including the UK and Australia, a hung parliament occurs when no single political party wins a majority in the House of Commons or the House of Representatives, respectively. In multi-party systems, particularly where proportional representation is employed, it is rare for a single party to hold a majority of the seats, and likewise rare for one party to form government on its own. Consequently, the concept of a “hung parliament” is largely irrelevant in these systems, as a legislature without a single-party majority is the norm.

In most parliamentary systems, a hung parliament is considered exceptional and is often seen as undesirable. However, in some contexts, a hung parliament may be seen as ideal – for example, if opinions among the voting public are polarized regarding one or more issues, a hung parliament may lead to the emergence of a compromise or consensus. If a legislature is bicameral, the term "hung parliament" is usually used only with respect to the lower house.

In the UK and Australia, if a hung parliament occurs, it is still possible for a government to be formed if a majority can be achieved through agreement with independent and/or minor party members. This type of government is known as a minority government.