Cass Business School (short for the Sir John Cass Business School) is the business school of City University London. Established in 1967 as the City University Business School (CUBS), the school changed its name in August 2002 following a donation from the Sir John Cass Foundation, an educational charity based in the City of London.

The school is divided into three faculties: the Faculty of Actuarial Science and Insurance, the Faculty of Finance and the Faculty of Management. It awards BSc (Hons), MSc, MBA and PhD degrees and is accredited by the Association of MBAs (AMBA) in the United Kingdom, the European Quality Improvement Scheme (EQUIS) in Europe, and the Association to Advance Collegiate Schools of Business (AACSB) in the United States. Cass is the largest European provider of specialist MSc degrees in financial services. The school’s Alumni Association has more than 31,000 members in 154 countries.

Cass is located close to the centre of London's financial and commercial district, the City of London. The school's stated aim is to be "the intellectual hub of the City" by forging links with financial institutions and multinational corporations as well as start-up businesses.

A business school is a university-level institution that confers degrees in Business Administration. They can also be known by such names as College of Business, College of Business Administration, School of Business, or School of Business Administration. A business school teaches topics such as accounting, administration, economics, entrepreneurship, finance, information systems, marketing, organizational behavior, public relations, strategy, human resource management, and quantitative methods.

They include schools of business, business administration, and management. There are four principal forms of business school.

Common degrees are as follows.

Some business schools center their teaching around the use of case studies (i.e. the case method). Case studies have been used in graduate and undergraduate business education for nearly one hundred years. Business cases are historical descriptions of actual business situations. Typically, information is presented about a business firm's products, markets, competition, financial structure, sales volumes, management, employees and other factors affecting the firm's success. The length of a business case study may range from two or three pages to 30 pages, or more.