Daga karni na 5 zuwa na 13, kudu maso gabashin Asiya ya ga jerin jihohi masu karfi wadanda suka yi matukar kokari wajen inganta addinin Buddha da fasahar Buddha tare da
addinin Hindu .Babban tasirin addinin Buddah yanzu ya zo ne kai tsaye ta hanyar teku daga yankin Indiya, ta yadda waɗannan masarautu da gaske sun bi imanin Mahāyāna.Misalai sun haɗa da masarautun ƙasa kamar Funan,
daular Khmer da
masarautar Thai ta Sukhothai da kuma masarautun tsibiri kamar Masarautar Kalinga,
daular Srivijaya , Masarautar Medang da Majapahit.Sufaye mabiya addinin Buddah sun yi tafiya zuwa
kasar Sin daga masarautar Funan a karni na 5 AZ, inda suka kawo ayoyin Mahayana, alamar da ke nuna cewa addinin ya riga ya kafu a yankin.Buddha Mahayana da Hindu sune manyan addinan daular Khmer (802-1431), jihar da ta mamaye mafi yawan yankin kudu maso gabashin Asiya a lokacinta.A ƙarƙashin Khmer, an gina haikali da yawa, duka biyun Hindu da Buddha, a cikin Cambodia da maƙwabtan Thailand.Ɗaya daga cikin manyan sarakunan Khmer, Jayavarman VII (1181-1219), ya gina manyan gine-ginen Buddha na Mahāyāna a Bayon da Angkor Thom.A cikin tsibirin Java na
Indonesiya , masarautun Indiyawa kamar Masarautar Kalinga (ƙarni na 6-7) sun kasance wuraren zuwa ga sufaye na China waɗanda ke neman rubutun Buddha.Malay Srivijaya (650-1377), daular Maritime da ke kan tsibirin Sumatra, ta karbi Mahāyāna da Vajrayāna Buddhism kuma ta yada addinin Buddha zuwa Java,
Malaya da sauran yankuna da suka ci.