Azulejo (Portuguese: [ɐzuˈleʒu, ɐzuˈlɐjʒu], Spanish: [asuˈlexo]; from the Arabic al-zillīj, الزليج)[1][2] is a form of Portuguese and Spanish painted tin-glazed ceramic tilework. Azulejos are found on the interior and exterior of churches, palaces, ordinary houses, schools, and nowadays, restaurants, bars and even railways or subway stations. They are an ornamental art form, but also had a specific functional capacity like temperature control in homes.

Panel of the Battle of Aljubarrota by Portuguese artist Jorge Colaço, 1922.

There is also a tradition of their production in former Portuguese and Spanish colonies in North America, South America, Goa (India), Lusophone Africa, East Timor, Macau (China), and the Philippines. Azulejos constitute a major aspect of Portuguese architecture to this day and are fixtures of buildings across Portugal and its former territories. Many azulejos chronicle major historical and cultural aspects of Portuguese history.