Jeddah (English: JED-ə), alternatively transliterated as Jedda, Jiddah or Jidda ( JID-ə; Arabic: جِدَّة‎, romanized: Jidda, Hejazi pronunciation: [ˈdʒɪd.da]), is a city in the Hejaz region of western Saudi Arabia and the country's commercial center. It is not known when Jeddah was founded, but Jeddah's prominence grew in 647 when the Caliph Uthman made it a travel hub serving Muslim travelers going for Islamic pilgrimage to the holy city of Mecca. Since those times, Jeddah has served as the gateway for millions of pilgrims who have arrived in Saudi Arabia, traditionally by sea and recently by air. With a population of about 4,697,000 people as of 2021, Jeddah is the largest city in Makkah Province, the largest city in Hejaz, the second-largest city in the Saudi Arabia (after the capital Riyadh), and the ninth-largest in the Middle East. It also serves as the administrative centre of the OIC. Jeddah Islamic Port, on the Red Sea, is the thirty-sixth largest seaport in the world and the second-largest and second-busiest seaport in the Middle East (after Dubai's Port of Jebel Ali).

Jeddah is the principal gateway to Mecca, the holiest city in Islam, 65 kilometers (40 mi) to the east, while Medina, the second-holiest city, is 360 kilometers (220 mi) to the north. Economically, Jeddah is focusing on further developing capital investment in scientific and engineering leadership within Saudi Arabia, and the Middle East. Jeddah was ranked fourth in the Africa, Middle East, and 'stan countries region in the Innovation Cities Index in 2009.

Jeddah is one of the Saudi Arabia's primary resort cities and was named a Beta world city by the Globalization and World Cities Study Group and Network (GaWC). Given the city's close proximity to the Red Sea, fishing and seafood dominate the food culture unlike other parts of the country. In Arabic, the city motto is "Jeddah Ghair", which translates to "Jeddah is different". The motto has been widely used among both locals as well as foreign visitors.