Yes, Thrift Savings Plan contributions are taxable, but the question is when. If you contribute to a traditional TSP, the money goes in pre-tax and you pay federal income tax when you withdraw it in retirement. If you contribute to a Roth TSP, the money is taxed in the year you earn it, and qualified withdrawals later come out free of federal income tax. The choice you make at contribution time locks in which side of retirement carries the tax bill.
Federal tax law treats the Thrift Savings Fund the same as a private-sector 401(k) trust, so the contribution and distribution rules that apply to 401(k) plans apply to the TSP.1Office of the Law Revision Counsel. 26 USC 7701 – Definitions
Traditional TSP Contributions: Taxed at Withdrawal
Traditional contributions come out of your paycheck before federal income tax withholding. That lowers your adjusted gross income for the year and reduces your current tax bill dollar-for-dollar. Your investments grow inside the account without being taxed year to year.
The bill comes due in retirement. Every dollar you withdraw from a traditional TSP balance counts as ordinary income in the year you receive it. That includes both the contributions and every penny of investment growth. There is no capital gains rate and no special treatment. If you pull out $40,000 in a given year, that full amount stacks on top of your other income and is taxed at whatever brackets it fills. Retirees who haven’t planned for this sometimes find that their usable income is noticeably less than the account balance suggested.
Roth TSP Contributions: Taxed Now, Tax-Free Later
Roth TSP contributions work in reverse. You contribute after-tax dollars, so there is no deduction for the year you make the contribution. In return, qualified withdrawals of both contributions and earnings are completely free of federal income tax.2Office of the Law Revision Counsel. 26 USC 402A – Optional Treatment of Elective Deferrals as Roth Contributions
A distribution counts as “qualified” only when two conditions are met. First, at least five years must have passed since January 1 of the calendar year you made your first Roth TSP contribution. Second, you must be at least 59½, have a permanent disability, or have died (in which case your beneficiary receives the benefit).3The Thrift Savings Plan (TSP). Roth In-Plan Conversions If you withdraw Roth earnings before meeting both requirements, those earnings are taxed as ordinary income and may also face the 10% early withdrawal penalty.
Under the SECURE 2.0 Act, starting with tax years after December 31, 2023, Roth TSP balances are no longer subject to required minimum distributions during your lifetime.4Federal Register. Elimination of Mandatory Roth Distributions Your Roth TSP balance can now keep growing tax-free for as long as you live.
Agency and Service Matching Always Goes Into the Traditional Balance
Here is the detail that catches many Roth contributors off guard. If you are a FERS or BRS participant, all agency and service contributions go into your traditional balance regardless of whether you elected Roth for your own deferrals.5The Thrift Savings Plan (TSP). Traditional and Roth TSP Contributions Even a 100% Roth contributor will end up with a traditional balance that is fully taxable on withdrawal. Plan for that when you estimate your future tax liability.
Combat Zone Contributions: A Special Case
Uniformed service members who contribute from tax-exempt combat zone pay get unusual treatment. For a traditional TSP, the contributions themselves were never taxed, so they are not taxed again on withdrawal; only the earnings are taxable. For a Roth TSP, both the contributions and the earnings come out tax-free in a qualified distribution, which makes combat zone Roth contributions one of the most tax-efficient savings opportunities available to service members.6Military OneSource. Combat Pay and Your Thrift Savings Plan Your TSP statements track the tax-exempt portion separately, which matters for the taxable share of future distributions.
The 10% Early Withdrawal Penalty and Its Exceptions
Taking money from your TSP before age 59½ generally triggers a 10% additional tax on the taxable portion, on top of any ordinary income tax you owe.7Office of the Law Revision Counsel. 26 USC 72 – Annuities; Certain Proceeds of Endowment and Life Insurance Contracts Several exceptions apply.
Separation at Age 55 or Later
If you separate from federal service during or after the calendar year you turn 55, distributions from your TSP are exempt from the 10% penalty. You do not need to wait until 59½.8Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions The word that matters is “separation.” Leave your job at 54 and request a distribution at 56, and the exception does not apply, because you separated before the year you turned 55.
Public Safety Employees
Federal public safety employees who separate during or after the year they turn 50 avoid the penalty. Under SECURE 2.0, the exception also covers public safety employees with at least 25 years of federal service in a TSP-eligible position, regardless of age.9Thrift Savings Plan. Changes to Tax Rules About TSP Payments Your agency has to identify you as a public safety employee for the TSP to apply the exception.
Substantially Equal Periodic Payments
If you have separated from service and need regular income before 59½, you can set up a series of substantially equal periodic payments based on your life expectancy. Follow the schedule without modification for at least five years or until you reach 59½, whichever is later, and the 10% penalty does not apply. The IRS allows three calculation methods: the required minimum distribution method, fixed amortization, and fixed annuitization.10Internal Revenue Service. Substantially Equal Periodic Payments Deviating from the schedule before the required period ends retroactively triggers the penalty on every distribution taken under the arrangement.
Other Exceptions
The 10% penalty also does not apply to distributions on account of permanent disability, to beneficiaries after the participant’s death, or under a qualified domestic relations order. In-service withdrawals taken at or after age 59½ avoid the penalty by definition.
Required Minimum Distributions From the Traditional Balance
Once you leave federal service and reach a certain age, the IRS requires you to take annual withdrawals from your traditional TSP balance. The starting age depends on your birth year:
- Born before 1960: RMDs begin at age 73, with the first distribution due by April 1 of the year after you turn 73 and have separated.
- Born in 1960 or later: RMDs begin at age 75, with the same April 1 deadline.11The Thrift Savings Plan (TSP). Taking Money From Your Account
The annual amount is calculated using IRS life expectancy tables and your prior-year-end account balance. Withdraw less than required and the IRS imposes a 25% excise tax on the shortfall. The penalty drops to 10% if you correct the mistake within the correction window, which generally runs through the end of the second year following the year the tax was imposed.12Office of the Law Revision Counsel. 26 USC 4974 – Excise Tax on Certain Accumulations in Qualified Retirement Plans Roth TSP balances no longer generate lifetime RMDs, so only the traditional balance triggers this obligation.
Withholding on Distributions
The TSP withholds federal income tax on most taxable distributions, but the rate depends on how you take the money. Single lump-sum payments and installments expected to last fewer than 10 years carry a mandatory 20% federal withholding on the taxable portion, and you cannot opt out. Installments expected to last 10 years or more are withheld as if you are single with no dependents unless you file an election choosing a different rate.9Thrift Savings Plan. Changes to Tax Rules About TSP Payments Withholding is only an estimate. Your actual tax bill depends on your total income for the year.
Rollovers Without a Tax Hit
You can move TSP funds to an IRA or another eligible employer plan without triggering current tax, but the method matters.
In a direct rollover, the TSP sends the money straight to your new plan or IRA custodian. Nothing is withheld, and the funds keep their tax status. A traditional balance rolled into a traditional IRA stays tax-deferred. A Roth balance rolled into a Roth IRA or another Roth employer plan stays tax-free, assuming the five-year rule is eventually satisfied.9Thrift Savings Plan. Changes to Tax Rules About TSP Payments One exception: if a spouse beneficiary rolls a traditional TSP balance into a Roth IRA, the entire amount is taxable that year, because Roth IRAs only hold after-tax money.
In an indirect rollover, the TSP pays you directly and must withhold 20% of the taxable amount. You then have 60 days to deposit the full pre-withholding distribution into another qualified plan or IRA. Deposit only the net amount you received and the 20% that was withheld becomes a taxable distribution, potentially with a 10% early withdrawal penalty on top if you are under 59½.9Thrift Savings Plan. Changes to Tax Rules About TSP Payments To keep the rollover whole, you would need to make up the withheld amount from other savings.
State Taxes Are a Separate Question
Federal rules are only half the picture. Most states with an income tax treat TSP distributions as taxable, but the treatment varies. Some exempt retirement plan income above a certain age. Others offer partial exclusions that phase out at higher incomes. A handful of states have no income tax at all. The differences can amount to thousands of dollars per year, so check your state’s specific rules before retirement, especially if you are considering relocating.