401(k)退休福利计划，是美国于1981年创立一种延后课税的退休金帐户计划，美国政府将相关规定明订在国税法第401(k)条中，故简称为401(k)计划。美国的退休计划有许多类，像公务员、大学职员是根据其法例供应退休金，而401(k)只应用于私人公司的雇员。

计划是自愿性质，劳工可依其个人需求自由选择政府核准过的的个人退休金计划。内容为要求雇员定期拨金钱至个人的退休计划，同时公司将拨部分资金至每位雇员的401(k)，直到雇员离职。而雇员可自行决定拨钱的数目多寡。

In the United States, a 401(k) plan is the tax-qualified, defined-contribution pension account defined in subsection 401(k) of the Internal Revenue Code. Under the plan, retirement savings contributions are provided (and sometimes proportionately matched) by an employer, deducted from the employee's paycheck before taxation (therefore tax-deferred until withdrawn after retirement or as otherwise permitted by applicable law), and limited to a maximum pre-tax annual contribution of $18,000 (as of 2015).