In the U.S. payroll withholding taxes are the taxes that an employer is required to deduct from its employees' gross wages, salaries, bonuses, and other compensation.
The typical payroll withholding taxes include each employee's portion of the Social Security and Medicare taxes (also referred to as FICA), federal income tax, and often state income tax. (A few cities and states may also require additional payroll taxes.)
After deducting the payroll withholding taxes from its employees, the employer is required to remit the amounts in a timely manner to the appropriate government.
In addition to payroll withholding taxes, most employers also withhold nontax amounts for insurances, savings plans, union dues, court-ordered garnishments, and so on.