Sanaa, officially the Sanaa Municipality, is the de jure capital and largest city of Yemen. The city is the capital of the Sanaa Governorate, but is not part of the governorate, as it forms a separate administrative unit. At an elevation of 2,300 metres (7,500 ft), Sanaa is one of the highest capital cities in the world and is next to the Sarawat Mountains of Jabal An-Nabi Shu'ayb and Jabal Tiyal, considered to be the highest mountains in the Arabian Peninsula and one of the highest in the Middle East.

Sanaa has a population of approximately 3,292,497 (2023), making it Yemen's largest city. As of 2020, the greater Sanaa urban area makes up about 10% of Yemen's total population. The Old City of Sanaa, a UNESCO World Heritage Site, has a distinctive architectural character, most notably expressed in its multi-story buildings decorated with geometric patterns. Al-Saleh Mosque, the largest in the country, is located in the southern outskirts of the city.

According to the Yemeni constitution, Sanaa is the capital of the country, although the seat of the Yemeni government moved to Aden, the former capital of Democratic Yemen, in the aftermath of the Houthi occupation. Aden was declared the temporary capital by then-president Abdrabbuh Mansur Hadi in March 2015.