Do I have to let an employee have time off for jury duty?

Yes, California Labor Code Section 230(a) provides that an employer may not discriminate against an employee for taking time off to serve as required by law in an inquest jury or trial jury, if the employee, prior to taking time off, gives reasonable notice to the employer that they're required to serve.

Absences from work for jury duty are protected by law; you cannot deny the employee the time off. This requirement applies to all employers, regardless of size.

Whether wages must be paid to an employee who takes time off for jury duty depends on the employee's status as exempt or nonexempt.