A Staff Professional Workshop on "Effective Lesson Observation and Evaluation" conducted by Professor Ko Po Yuk was held on 10 January, 2024 for more than 60 teachers of Hong Kong Chinese Women's Club College. Professor Ko introduced the theories, framework, and conferencing skills of lesson observation and evaluation. Using examples and video clips from different subjects, Professor Ko explained and discussed with the teachers how to apply the relevant theories of lesson observation in conducting school-based lesson observation activities for enhancing teaching effectiveness. The teacher participants commented that the workshop helped them understand the purpose and focus of lesson observation, master the post-lesson conferencing skills, and the concrete examples promoted their reflection on how to effectively design classes.