This comparative study explores the efficacy of various professional development (PD) models for teacher educators in New Delhi, focusing on in-service training, knowledge-for-practice, and knowledge-in-practice approaches. Through a comprehensive mixed-methods research design, data were collected from 150 teacher educators using surveys, with additional qualitative insights gathered from 30 in-depth interviews. The research aims to determine which PD models are most effective in enhancing professional competencies and improving instructional practices among teacher educators. The findings reveal distinct differences in the effectiveness of these PD models. In-service training, characterized by its theoretical and foundational approach, was deemed less effective due to its limited practical application and lack of ongoing support. Conversely, knowledge-for-practice models provided a strong theoretical foundation but were similarly constrained by insufficient practical integration. Knowledge-in-practice models emerged as the most effective, significantly improving teaching practices through practical, experiential learning and direct classroom application. Quantitative results demonstrated substantial improvements in lesson planning, instructional strategies, student assessment, and classroom management among educators engaged in knowledge-in-practice PD. Qualitative data reinforced these findings, with educators reporting increased confidence, enhanced student engagement, and better classroom management skills. This study underscores the critical need for PD programs that are continuous, collaborative, and closely aligned with the practical realities of teaching. The insights gained from this comparative analysis provide valuable recommendations for educational institutions and policymakers to design and implement PD initiatives that effectively enhance teacher educators professional growth and contribute to improved educational outcomes. These findings advocate for a more integrated approach to PD, ensuring it remains relevant, practical, and supportive of sustained professional development.