A stockbroker is a professional trader who buys and sells shares on behalf of clients. The stockbroker may also be known as a registered representative or an investment advisor.

Most stockbrokers work for a brokerage firm and handle transactions for a number of individual and institutional customers. Stockbrokers are often paid on a commission basis although compensation methods vary by employer.

Brokerage firms and broker-dealers are also sometimes referred to as stockbrokers. This includes both full-service brokers and discount brokers, who execute trades but do not offer individualized investing advice.