40 ILCS 5/17-125
Upon certification by the Employer of a member's resignation or termination prior to completion of the minimum term of service required to establish eligibility for a pension and on written application therefor, a teacher shall be paid a refund of all the amounts the member has contributed to the Fund, less any former refund that has not been repaid.
Upon certification by the Employer of the member's resignation or termination after completion of the minimum term of service required to establish eligibility for a pension and on written application therefor, a teacher shall be paid a refund of all the amounts the member has contributed, less (1) any former refund that has not been repaid, and (2) pension payments received, provided the member has executed and delivered to the Board a written acknowledgment of forfeiture of all service credit and rights to pension payments . Thereupon, the member shall have no further interest in or claim against the Fund.
A request for refund shall be considered valid if the member's withdrawal from service occurred at least 2 months prior to the filing of such request.
Upon retirement of a teacher either on immediate or deferred pension, if the teacher is not then married, or if the member's spouse or children do not meet the qualifying conditions for a survivor's or children's pension , the total amount contributed by the member or otherwise paid by deductions from salary for survivor's pension, shall be refunded to the member , without interest. No survivor's or children's pension rights shall be effective thereafter in such a case.
During a teacher's term of service, no refund is payable except contributions made in error.
40 ILCS 5/17-125