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Our Mission

Substitute Teacher Service, Inc. (STS) is a customer service-based organization, dedicated to providing our clients with a workable, cost-effective solution to their substitute professional and support personnel needs as well as giving exposure to our employees in the many districts we service.   STS is the foremost locator of substitute teachers, teacher aides, and support personnel in Pennsylvania. At STS, we supply our client school districts with the professional and support personnel they need, when they need them.

Our History

STS has remained loyal and true to its locally owned and operated Pennsylvania roots and family-run dynamic, since its beginning in 1994.  Started 30 years ago, within the Commonwealth, STS is the only solely Pennsylvania based substitute teacher service of its kind.  With a primary focus on excellent customer service, quality value, superb communication, and business staffing needs of the school district entity, STS implements core values while utilizing a modern approach to delivery.

We recruit from colleges and universities, major education job fairs, and local events, to maintain a plentiful pool of qualified professionals.  We take pride in our community involvement, outreach and interaction, and dedication to our Pennsylvania school districts.  We are fully committed to our mission and contributing to the continuous movement of changing lives through the power of education. 

Company Profile

STS is the largest employer and provider of substitute teachers and paraprofessionals in Pennsylvania. STS currently supplies personnel to over 80 school districts throughout the state.


STS recruits educational professionals from newly graduated teachers to certified retirees who serve as substitute teachers in the Pennsylvania school districts. Our recruiting efforts place over 7,000+ teaching professionals and paraprofessionals on our list at any given time.


STS fills over 2,500 jobs every day with teachers, paraprofessionals and support staff. Our numbers speak for themselves!  STS is powered by Frontline Education, formerly Aesop.



STS works in conjunction with the Department of Education to ensure that the professional staff we hire meet all of the requirements necessary for teaching and working in Pennsylvania school districts.


STS works with Intermediate Units to develop programs for our employees that help them meet state mandates, acquire training and other services they need in order to be successful.

Our Management Team

The management team of STS has over 120 combined years of experience in the temporary industry. Our expertise and recruiting practices in conjunction with employee retention give us a competitive edge over other staffing agencies.

STS examines the way different school districts handle their need for substitute staffing. We know that if we apply the same principles of recruitment and retention, we can provide a workable, cost-effective solution in supplying school districts with certified/qualified professionals.

Our team consists of business executives, human resources specialists, certified teachers, school district administrators, certified technical experts, and many talented professionals who bring the necessary skills to help STS achieve our mission and goals.

Our Locations

STS conducts business in the greater Delaware Valley area from its headquarters in Aston, Pennsylvania, with branch offices in Lancaster and satellite recruiting offices throughout the state. Our service offices are open 5 days a week, Monday through Friday from 6:00 a.m. until 5:00 p.m.

We can help you! Contact us at 800-357-SUBS (7827)