There are currently no federal legal requirements for paid sick leave. For companies subject to the Family and Medical Leave Act (FMLA), the Act does require unpaid sick leave. FMLA provides for up to 12 weeks of unpaid leave for certain medical situations for either the employee or a member of the employee's immediate family. In many instances paid leave under an employer’s paid time off (PTO) policy may be substituted for unpaid FMLA leave.

Employees are eligible to take FMLA leave if they have worked for their employer for at least 12 months; have worked for at least 1,250 hours over the previous 12 months; and work at a location where at least 50 employees are employed by the employer within 75 miles.

Because federal law does not require sick leave, if an employee quits their job before using all of their sick leave, the employer is not obligated to pay the employee for that time—unless the employer’s policy or state or other law requires the employer to pay the employee for unused sick leave.

Some states, cities, and counties may have laws that require employers to provide employees with paid sick leave.

In Massachusetts, the state law goes beyond the federal Family and Medical Leave Act (FMLA) by requiring employers to provide paid sick leave. Under the Massachusetts Earned Sick Time Law, employers with 11 or more employees must provide paid sick leave, while smaller employers must provide unpaid sick leave. Employees earn 1 hour of sick leave for every 30 hours worked, up to 40 hours per year. This leave can be used for the employee's own illness or that of a family member, as well as for medical appointments or to address issues related to domestic violence. If an employee leaves their job, Massachusetts law does not require employers to pay out unused sick leave unless the employer's policy states otherwise. This means that the payout of unused sick leave upon an employee's departure is generally a matter of company policy rather than state law.