The Thrift Savings Plan (TSP) is a retirement savings plan designed for federal employees and members of the uniformed services. It allows participants to save money for retirement through tax-deferred contributions, meaning they won't pay taxes on the money until they withdraw it. The TSP offers various investment options, including government securities and stock index funds, helping individuals grow their savings over time. Participants can contribute a portion of their salary to the TSP, and many employers provide matching contributions. This plan is similar to private sector 401(k) plans, making it a valuable tool for building a secure financial future for those in government service.