The aim of this study was to investigate the effects of applying a Peer-Led Team Learning Instructional Model (PLTL) to the prospective primary school teachers in teaching the simple electrical circuits subject on the seven principles for good practice. This study used the three-group Solomon Experimental Design. The study participants were sophomore level prospective teachers from the Department of Primary School Teaching at a state university. The control group (CG) was applied close-ended experimental method, while the experimental groups (EG1 and EG2) was applied the PLTL. The data collection tool of the study was used "Seven Principles Opinion Scale for Good Practice" (SPOS) developed by Bishoff (2010). The SPOS was used for the pre-test of EG1 and CG, and for the post-test of EG1, EG2 and CG. According to the post-test, the experimental groups applying the PLTL were better than the control group in the "Encouraging Student-Faculty Contact", "Encouraging Cooperation among Students", "Respecting Diverse Talents/Ways of Learning", "Encouraging Active Learning", and "Giving Prompt Feedback" principles. The PLTL is effective in attaining the objectives of the seven principles for good practice. It is recommended that further studies on PLTL should be conducted in order to contribute to the relevant literature by investigating the teaching experience that leaders gain in applying the principles necessary for a good education.