Willemstad serves as the capital and largest city of Curaçao, an island nation in the southern Caribbean Sea that is a constituent country of the Kingdom of the Netherlands. It also previously held the status of capital for the Netherlands Antilles before that entity dissolved in 2010. The city is situated on the island's southern coast, defined by its natural deep-water harbour and strategic location near Venezuelan oilfields.

The city's origins trace back to 1634 when the Dutch West India Company captured the island from Spain, establishing the walled settlement of Punda. The name Willemstad, meaning William Town, was first recorded in 1680 in honour of Dutch princes. Suburbs like Otrobanda and Pietermaai developed over subsequent centuries, with the historic centre later designated a UNESCO World Heritage Site for its unique architecture.

The urban landscape consists of four main quarters: Punda and Otrobanda, separated by Sint Anna Bay, and Scharloo and Pietermaai across the Waaigat harbour. The city features colonial architecture influenced by Dutch styles and is home to the Curaçao synagogue, the oldest surviving in the Americas. The Queen Emma Bridge connects the primary districts of Punda and Otrobanda.

Tourism is a major industry, drawing visitors to the UNESCO-listed city centre, several casinos, and beaches like Baya Beach. The area offers museums such as Museum Kura Hulanda and the Maritime Museum, which detail the region's history including the Atlantic slave trade. The historic waterfront and colonial buildings provide a distinct cultural atmosphere for cruise ship tourists and residents alike.

Willemstad had a population of 136,660 as of 2011, accounting for approximately 90% of Curaçao's total inhabitants. Its economy relies on oil refining, financial services, and tourism, supported by Curaçao International Airport located 12 kilometres north. The city experiences a hot semi-arid climate with hot summers and winters, making it a year-round destination.