研究目的　近年來，臺灣部分學校教師借鏡國外經驗，實施共同備課、公開觀課與集體議課，但其實施目的與關注焦點以及是否著實提升自己的教學專業，是臺灣推動此教育改革之當下需要檢視的。本研究之目的在於瞭解臺灣國中教師在共同備課、公開觀課與集體議課的實施目的、關注內容以及在教學專業成長的知覺。研究設計／方法／取徑　本研究自編問卷，針對臺灣國中教師進行調查研究，以縣市進行分層立意叢集方式抽取2,374 位教師，其中753 位教師有共備、觀課與議課的完整參與經驗，741 位教師從未有過類似經驗，其餘則有部分參與經驗。本研究以獨立樣本t 考驗和Friedman 等級變異數分析「完整參與」和「從未參與」的兩群教師，在實施目的、關注內容和教學專業成長知覺上的差異以及在其分項知覺的高低情形。研究發現或結論　本研究發現完整參與教師在實施目的、關注內容和教學專業成長知覺均顯著高於未曾參與的教師。而完整參與教師在實施目的之分項（教學專業能力、學科教材知識和學生學習成效）均有等同程度的知覺，然而，從未參與的教師較少以促進學生學習成效為目的。在關注內容上，兩群教師仍比較在乎教學策略的應用，較少關注學科知識與學習能力的培養。研究原創性／價值　臺灣學校早期的教學觀摩多是行政作為，教師是被觀察的對象，而學校教師的專業成長多為聆聽知識或資訊的活動。透過本研究的實證結果，可以更瞭解參與共同備課、公開觀課與集體議課的教師之國中教師的協同經驗，並提出透過教師協同進行教學專業成長的改善建議。

Purpose Many Taiwanese teachers have begun implementing the activities of collaborative lesson preparation, open classroom observation, and discussion on completed lessons, according to teacher collaborative practices in foreign schools. The perceptions on the purposes of and concerns about these activities as well as their effectiveness in the professional development of teachers warrant investigation. Therefore, this study compared Taiwanese teachers experienced in collaborative lesson study and their inexperienced counterparts. Design/methodology/approach A survey was conducted to collect data from 2,374 secondary school teachers from 21 regions by using stratified random cluster sampling. Of these teachers, 753 were experienced in collaborative lesson study, 741 were inexperienced, and the remaining teachers were partly experienced. The independent-samples t test and Friedman rank analysis were used to compare the ranking of various variables between the experienced and inexperienced teachers. Findings Significant differences were observed between the study groups in the perceptions on the purposes of and concerns about collaborative activities and the effectiveness in professional development. Friedman rank analysis of the experienced teachers revealed identical rankings on the purposes of collaborative activities, namely professional ability, subject matter knowledge, and students' learning effectiveness. However, students' learning effectiveness was less considered by inexperienced teachers in collaborative activities. Moreover, regardless of whether collaborative activities were implemented, the teachers were more concerned about instructional strategies than subject matter and learner abilities when collaborating. Originality/value Previously in Taiwan, classroom teaching demonstration was considered an administrative affair, in which the focus was often on the demonstrating teachers' behaviors rather than students' learning performance. The present findings provide a more comprehensive outlook on the experiences of Taiwanese secondary school teachers in collaborative lesson preparation, open classroom observation, and discussion on completed lessons, thus enabling further improvements in teacher collaborations for professional development.