The Enrichment Experiences in Engineering (E[superscript 3] ) summer teacher program is hosted by the Dwight Look College of Engineering at Texas A&M University and is designed to provide engineering research experiences for Texas high school science and mathematics teachers. The mission of the E[superscript 3] program is to educate and excite teachers about the field of engineering so that they can introduce engineering concepts to their students and encourage them to consider a career in engineering. The E[superscript 3] program received funding from the National Science Foundation (NSF) Research Experiences for Teachers (RET) program from 2003 through 2013, and during that time, a total of 150 teachers participated in the program. Most of the teachers were from schools with large minority-student populations (average 83% Hispanic and/or African American; average 69% economically-disadvantaged). This paper presents evaluation findings to assess long-term impact of the E[superscript 3] program on teachers who participated in one of the NSF-funded E[superscript 3] programs during the 2003-2012 timeframe. The two research questions central to the study design were: (1) What is the long-term impact of the E[superscript 3] summer program on teachers who participated in the program? and (2) To what extent did the teachers who participated in the E[superscript 3] summer experience impact student understanding, awareness and perceptions of the engineering field? The assessment tools included a series of focus group interviews and an anonymous online survey. The focus group sessions were conducted by the E[superscript 3] external evaluator during annual E[superscript 3] workshops where teachers from previous E[superscript 3] cohorts were invited to attend. The anonymous online survey was administered in Fall 2013 by the external evaluator. Evaluation findings document that the E[superscript 3] program has been successful in educating teachers about the engineering field and that, in the long term, teachers continue to promote engineering to their students as a career option. However, the teachers have experienced challenges when trying to implement their E[superscript 3]-developed classroom lessons in subsequent academic years. Recommendations to remediate this issue are provided. Although NSF funding concluded in 2013, the College continues to offer E[superscript 3] research experiences to high school mathematics and science teachers using other financial resources.