The St. Catharines Public Library is a public library system that provides service to residents of St. Catharines, Ontario. The library has four branches. Materials available for loan include books, films, musical instruments, and video games.

As early as 1888, various locations were rented for library use, but there were no permanent structures. The first dedicated building for the library opened in 1905 in Downtown St. Catharines, where the Robert S.K. Welch Courthouse has since replaced it. It was a Carnegie library. This building was expanded in 1939, 1940, and 1965, as a result of the growing population in the city. When Port Dalhousie, Merritton, and Grantham were amalgamated into the city in 1961, there was even greater demand for better library infrastructure. This led to that building closing in 1971 and being replaced by the current central branch. It was named the centennial branch to celebrate the centennial anniversary of the city's founding. In 1976, the library buried a time capsule to commemorate the occasion. There was also a sundial placed aboveground. In 2021, the sun dial was stolen from the premises. The time capsule is still intact and will be opened in 2076.

In 2022, the central branch received two robots from a local restaurant that are used to carry items across the library. In 2023, the branch in Port Dalhousie launched a program where the library remained open during unstaffed hours. This program expanded access to the library from three days to six days a week. These changes were made permanent in 2024. As of September 2024, residents from Niagara Falls, Niagara-on-the-Lake, Port Colborne, Thorold, Wainfleet, and Welland could borrow items from the library.

In 2021, the central library branch installed barriers and gates around the library, with the intention of deterring homeless people and acts of vandalism. The City of St. Catharines budgeted 50,000 dollars for these renovations. These renovations were criticized for "excluding the homeless as members of the public".

As of 2023, further renovations are planned, with a budget of 4.8 million dollars. A particular focus of these renovations is expanding community areas within the library. More than 100,000 physical items have been removed to make room for these spaces, with a greater emphasis being placed on access to digital materials. 65,000 of the removed items were duplicate materials. Bookshelves will be reduced in height and aisles will be widened as accessibility features. Local historians have criticized this weeding process for removing access to vital information in regards to their research. An estimated ten percent of materials have been removed from the library's special collections. Historians have also criticized the lack of public consultation in regards to these discarded materials.

• Hostile architecture
• List of Carnegie libraries in Canada
• List of public libraries in Ontario
• Thorold Public Library
• Niagara Falls Public Library (Ontario)

• Official website

43°09′37″N 79°14′46″W / 43.1604°N 79.2460°W / 43.1604; -79.2460