Barclays Investment Bank (trading as Barclays, formerly Barclays Capital) is a British multinational investment bank headquartered in London, United Kingdom and a division of Barclays. It provides financing and risk management services to large companies, institutions and government clients. It is a primary dealer in U.S. Treasury securities and various European Government bonds.

Barclays is led by co-CEOs Rich Ricci and Jerry del Missier. Barclays Capital had 2004 income of GBP 3.4 billion/USD 6.4 billion primarily driven by the structured tax and rates businesses.

In mid-March 2012, Barclays Capital, Barclays Wealth, and Barclays Corporate began transitioning to a single Barclays brand to serve clients more easily and efficiently, rather than sustaining the cost and complexity of multiple brands. Barclays Capital is now called Barclays Investment Bank, using simply the Barclays logo.

Barclays Investment Bank has offices in over 29 countries, and since the acquisition of Lehman Brothers' main U.S. division in September 2008, employs over 20,000 people, over 7,000 people work in the IT division. This has significantly increased Barclays' presence in North America.