The Qatar diplomatic crisis was a high-profile incident involving the deterioration of ties between Qatar and the Arab League between 2017 and 2021. It began when Saudi Arabia, the United Arab Emirates, Bahrain, and Egypt simultaneously severed their bilateral relations with Qatar and subsequently banned Qatar-registered aircraft and Qatari ships from utilizing their sovereign territory by air, land, and sea; this involved the Saudis' closure of Qatar's only land crossing, initiating a de facto blockade of the country. Tensions between the two sides came to a close in January 2021, following a resolution between the Saudis and the Qataris.

Qatar, officially the State of Qatar, is a country in West Asia. It occupies the Qatar Peninsula on the northeastern coast of the Arabian Peninsula in the Middle East; it shares its sole land border with Saudi Arabia to the south, with the rest of its territory surrounded by the Persian Gulf. The Gulf of Bahrain, an inlet of the Persian Gulf, separates Qatar from nearby Bahrain. The capital is Doha, home to over 80% of the country's inhabitants, and the land area is mostly made up of flat, low-lying desert.