在現代東南亞，馬來西亞是其中一個國家，漢傳和上座部長期並存，並逐漸形成不同程度的融合狀態。雖然馬來西亞佛教社群確以華人為主，但是上座部在大馬佛教的角色，與漢傳佛教不遑多讓，而在好些側面上猶有過之。本文將探討泰暹、緬甸及斯里蘭卡三系上座部是如何成為馬來西亞佛教的一環，討論雖然會涉及三系傳入的渠道和歷史背景，但探討的重心是落在這三系上座部是如何跨過族群界線，造成對原先以華人為主的佛教徒社群，在宗教信仰內涵、組織結構及實踐方式上的改變，同時亦會探討三系之間在宗教組成上的分工，及其與華人佛教社群之間的不同關係，並就其對大馬佛教的進一步可能影響，稍作說明。全文探討的重心放在上座部原先作為外來的移民宗教或本土的少數族群宗教，是如何「出現」於現代的馬來亞，跨過族群界限，以不同方式進入並融合於以華人為主的馬來西亞佛教社群，同時亦塑造著馬來西亞的現代佛教。

In contemporary southeast Asia, Malaysia is one country where Chinese and Theravāda Buddhist traditions have long coexisted, and gradually they have come to exist in a state of fusion, with varying degrees of difference. Although the majority of the Buddhist community in Malaysia certainly is ethnic Chinese, Theravāda Buddhism is not overshadowed by its Chinese counterpart in its social role, and in many regards surpasses it. This article will explore how the Burmese, Thai, and Sri Lankan traditions of Theravāda have become integral to Malaysian Buddhism. Although the discussion will involve the transmission path and the historical background of the schools, the heart of the analysis is how these three schools transcend ethnic boundaries, creating changes in religious beliefs, structures, and practices in a Buddhist communities concentrated on the Chinese ethnicity. At the same time, the article explores the division of labor in religious formation of the three schools, as well as their different relationships with Chinese Buddhist communities. Moreover, the article touches on the schools’ potential influence in the future. The emphasis of the discussion is placed on how the Theravāda traditions, which originally served as religions of foreign immigrants or indigenous religions of ethnic minorities, “appeared” in contemporary Malaysia and has transcended ethnic boundaries. Through different methods, these schools spread and fused together with Malaysian Buddhist communities concentrated on the Chinese ethnicity. Meanwhile, they are molding contemporary Buddhism in Malaysia.