為因應少子化導致學生人數漸減的趨勢，以及有效整合、善用學校資源，提供學生適性學習的機會，實施混齡教學有其重要性。本研究進行文獻分析、課室觀察及訪談，探討現行實施混齡教學的原因、方式與支持措施，並提出具體建議。研究發現以下三點，首先，混齡教學的原因可分為：因教育理念而實施混齡教學、因現實考量而實施混齡教學；混齡教學的實施方式至少包括：探究式教學、協同教學、合作學習、差異化教學法。另外，混齡教學的支持措施則從教師專業成長、課程規畫、學校行政支持三方面進行分析與論述。整體而言，混齡教學的實施不論在師資培育、教師專業成長、課程規畫、教學實施、行政措施等方面，皆需有更多的支持與配套。關於國中小混齡教學之研究在國內仍屬於初探階段，期待未來能有更多不同面向與不同研究方法之相關研究投入，俾使教育研究社群對於混齡教學能有更多的理解與運用。

As a result of low birth rate and population decline, mixed-age teaching is critical for accommodating the needs of classes with fewer students and for effectively integrating and utilizing school resources to provide students with adaptive learning opportunities. Through literature analysis, classroom observations, and interviews, the underlying reasons for mixed age teaching, methods of implementation and support measures employed by schools are explored. The findings of this study are as follows: 1) The justifications for mixed-age teaching are based on educational philosophy and practical considerations; 2) mixed-age teaching is implemented through four approaches; namely, inquiry-based instruction, team teaching, cooperative learning, and differentiated instruction; and 3) measures for supporting mixed-age teaching can be analyzed and discussed from three aspects: teachers’ professional development, curriculum planning, and school administration support. Overall, implementing mixed-age teaching requires further support on aspects of pre-service teacher education, professional development, curriculum planning, teaching implementation, and administrative measures. Studies on mixed-age teaching in elementary and junior high schools in Taiwan are preliminary. The results of the studies may assist the educational research community in understanding and implementing mixed-age teaching.