40 ILCS 5/16-132
A member who has at least 20 years of creditable service is entitled to a retirement annuity upon or after attainment of age 55. A member who has at least 10 but less than 20 years of creditable service is entitled to a retirement annuity upon or after attainment of age 60. A member who has at least 5 but less than 10 years of creditable service is entitled to a retirement annuity upon or after attainment of age 62. A member who (i) has earned during the period immediately preceding the last day of service at least one year of contributing creditable service as an employee of a department as defined in Section 14-103.04, (ii) has earned at least 5 years of contributing creditable service as an employee of a department as defined in Section 14-103.04, and (iii) retires on or after January 1, 2001 is entitled to a retirement annuity upon or after attainment of an age which, when added to the number of years of his or her total creditable service, equals at least 85. Portions of years shall be counted as decimal equivalents.
A member who is eligible to receive a retirement annuity of at least 74.6% of final average salary and will attain age 55 on or before December 31 during the year which commences on July 1 shall be deemed to attain age 55 on the preceding June 1.
A member meeting the above eligibility conditions is entitled to a retirement annuity upon written application to the board setting forth the date the member wishes the retirement annuity to commence. However, the effective date of the retirement annuity shall be no earlier than the day following the last day of creditable service, regardless of the date of official termination of employment; however, upon written application within 6 months after the effective date of this amendatory Act of the 103rd General Assembly by a member or annuitant, the creditable service and earnings received in the last fiscal year of employment may be disregarded when determining the retirement effective date and the retirement benefit as long as such employment is for (1) less than 10 days in length; (2) less than $2,500 in creditable earnings; and (3) the last fiscal year of employment includes only a fiscal year beginning on or after July 1, 2016 and ending before June 30,2023 . The retirement effective date may not, as a result of the application of this amendatory Act of the 103rd General Assembly, be earlier than July 1, 2016.
To be eligible for a retirement annuity, a member shall not be employed as a teacher in the schools included under this System or under Article 17, except (i) as provided in Section 16-118 or 16-150.1, (ii) if the member is disabled (in which event, eligibility for salary must cease), or (iii) if the System is required by federal law to commence payment due to the member's age; the changes to this sentence made by this amendatory Act of the 93rd General Assembly apply without regard to whether the member terminated employment before or after its effective date.
40 ILCS 5/16-132