A retirement investment plan for employees of certain non-profit organizations in which a contributor defers taxation on contributions until after withdrawal. Under a traditional 403(b), a worker places a portion of his/her pre-tax income into a 403(b) account and allows it to be invested. Taxation is deferred until withdrawal from the account, generally after retirement. 403(b)s are employee benefits, and workers must have a sponsoring employer such as a public school or a church in order to take advantage of one. They are the non-profit worker's equivalent of a 401(k).