Purpose: Hellison's (2003) Teaching Personal and Social Responsibility (TPSR) model has been embraced by physical education teachers for decades. The model's emphasis on empowerment and shifting responsibility to students has proven effective in varied settings (Hellison & Martinek, 2006). As the application and study of TPSR continues to expand within the US and internationally, there is an increasing need for tools to address implementation fidelity (Wright, 2008). To this end, we developed the TARE (Tool for Assessing Responsibility-based Education). The purpose of the current study was to test the instrument's use by observing 18 physical education lessons. Methods: Paired observations focused on two different teachers leading a variety of lessons for students in grades one through six. Analysis/Results: Reliabilities (i.e., percent agreement) were calculated for items contained in the three sections of the TARE. The first section consists of nine discrete teaching strategies that are consistent with TPSR such as providing students with leadership opportunities. A time-sampling methodology using five-minute intervals was employed to document the teachers' use of these strategies. Across the 18 lessons, 94 separate intervals were observed. Based on the total number of intervals, the percent agreement for items in section one ranged from 88% to 100%. Sections two and three of the TARE each contain four items that were rated holistically at the end of each lesson. Items were rated using a five-point Likert scale. The items in section two correspond to four themes Hellison (2003) describes as essential to TPSR, such as empowerment. The four items in section three correspond with the core responsibility levels of TPSR (Hellison, 2003) that can be observed in the class setting such as respect for the rights and feelings of others. Following Lewis et al. (1999), reliability on the holistic items in sections two and three was calculated as percent agreement within one on the five-point rating scale. Using this guideline, all holistic items met an acceptable level with reliabilities ranging from 78% to 100%. Conclusions: We conclude that the TARE is a reliable and feasible instrument for assessing TPSR implementation. While its primary application may be in TPSR research, the TARE could also be used in TPSR training. As the current national standards (NASPE, 2004) directly address personal and social responsibility as program outcomes, this instrument may have broader implications in the evaluation and improvement of K-12 physical education programs throughout the US. Keyword(s): physical education PK-12, research, youth-at-risk