Bua Yai (Thai: บัวใหญ่, pronounced [būa jàj], Northeastern Thai: บัวใหญ่, pronounced [būa ɲāj]) is a district (amphoe) in the northern part of Nakhon Ratchasima province, northern central Thailand.

Bua Yai dates back to the frontier town called Dan Nok (ด่านนอก).

In 1868, it was upgraded to Dan Nok District and the town center was moved to Ban Nong Lang Noi.

The presence of the railway spurred development of the village Ban Fat Fueay which became the new site of the district office in 1951.

The missing numbers are tambons which now form the districts Kaeng Sanam Nang, Sida, and Bua Lai.