The ruling party in a parliamentary system is the party or coalition of the majority in parliament. Within a parliamentary system, the majority in the legislature also controls the executive branch of government, thus leaving no possibility of dueling parties concurrently occupying the executive and legislative branches of government, such as in an American style presidential system where the party of the president does not necessarily also have a legislative majority.

Ruling party is also used to describe the party of one-party states, such as the Chinese Communist Party in China. A single-party state or one-party system or single-party system is a type of party system and form of government where only a single political party dominates the government and no opposition parties are allowed. ... Communist Party of China flag The Communist Party of China (Simplified Chinese: 中国共产党; Traditional Chinese: 中國共産黨; pinyin: Zhōnggu ngchǎndǎng) is the ruling party of the Peoples Republic of China. ...