The Powerhouse Museum, also known as the Museum of Applied Arts & Sciences (MAAS), is a collection of four museums in Sydney, owned by the Government of New South Wales. It is a contemporary museum of applied arts and sciences, exploring the intersections of design, innovation, science, and technology. Founded in 1879 as part of the Sydney International Exhibition, the institution is one of Australia’s oldest continuously operating museums.

The Powerhouse Museum operates across four sites in Sydney: Powerhouse Ultimo, Powerhouse Parramatta, Powerhouse Castle Hill and Sydney Observatory.

Powerhouse Ultimo, the museum’s home since 1988, is currently closed for major revitalisation. Powerhouse Parramatta, opening in 2026, will be the largest museum in the state of New South Wales. Powerhouse Castle Hill serves as the principal collection store and research centre, while Sydney Observatory continues to offer astronomy programs from its heritage-listed site at Observatory Hill.

Although often described as a science museum, Powerhouse holds one of Australia’s most significant and diverse museum collections, spanning over 500,000 objects across design, applied arts, science, and technology. Key areas include including decorative arts, science, communication, transport, costume, furniture, media, computer technology, space technology and steam engines.

Its collection and public presence have evolved across several key sites over time—from the Garden Palace in the Botanic Gardens, to the Agricultural Hall in the Domain, Technological, Industrial and Sanitary Museum of New South Wales (1879–1882), the Technological Museum (August 1893 – March 1988) on Harris Street, and eventually into the Powerhouse Ultimo, housed in the former Ultimo Power Station from 1988.

Much of the collection is stored and researched at Powerhouse Castle Hill, a publicly accessible facility open on weekends. Since 2019, Powerhouse has undertaken one of the largest museum digitisation projects in the world, making its vast collection more accessible through millions of high-resolution object photographs available online. This effort is extended through projects like Sounding the Collection, which captures the unique sounds of selected objects, offering new sensory ways to experience the collection.

Powerhouse Parramatta is currently under construction along the Parramatta River, is set to become the largest museum in New South Wales upon its anticipated opening in late 2026. The facility will feature over 18,000 square meters of exhibition and public space, including a 600-seat theatre, rooftop garden with telescopes, demonstration kitchen, and seven column-free exhibition spaces. Designed by Moreau Kusunoki and Genton, the project represents the most significant cultural infrastructure investment in NSW since the Sydney Opera House.

Powerhouse Ultimo, housed in a repurposed 1902 electric tram power station, has served as the museum's primary venue since its opening in 1988. In recent years, Powerhouse Ultimo has consistently ranked among the most visited museums in Oceania.