This paper reports on the use of teaching portfolios to assist in curriculum revision and the exploration of instructional practices used by middle school technology and engineering education teachers. Two new middle school technology and engineering education units were developed through the Engineering for All (EfA) project. One EfA unit focused on addressing world food shortages via the design and construction of urban vertical hydroponic farming systems, and the other focused on providing safe drinking water through the design and construction of water filtration and purification systems (modeled to reflect needs of people in a developing nation, in this case, Bangladesh). To explore the implementation of the new EfA units by teachers and to help with their revision, a new teaching portfolio instrument was developed, validated, and used. The teaching portfolios that participating EfA teachers compiled were evaluated based on a set of Design Teaching Standards that were developed for the project, and which grew out of the informed design teaching and learning model. Findings from the review of the teaching portfolios were used to (a) revise the curriculum, (b) create design-based teaching performance rubrics, and (c) develop specific materials for the professional development of prospective EfA teachers. Findings from this research project were also used to explore the strengths of middle school technology and engineering teachers and the challenges that they face when supporting students in doing engineering design in a social context.