Article 160 of the Federal Constitution of Malaysia defines a Malay as an individual who professes the religion of Islam, habitually speaks the Malay language, and conforms to Malay customs. However, this definition, central to the allocation of certain privileges to the Malays based on their special position as natives in Malaysia, is subject to ongoing debates and challenges. The issue of Malay indigeneity is frequently raised, therefore prompting this study to examine the formation of Malay ethnic identity within Malaysian legislation from the historical perspective. The findings found that the definition of Malays in Article 160 of the Federal Constitution was established based on the parameters outlined in the Federation of Malaya Agreement 1948. Prior to that, the definition of Malays was articulated according to the Malay Reserve Enactments. However, the definition of Malays in the Federal Constitution is more flexible compared to the Malay Reserve Enactments because the requirement of Malay descent is not stated as a condition for determining the characteristics of Malays. Therefore, the definition of Malays in the Federal Constitution has enabled the descendants of other ethnic groups of the Malay Archipelago and foreign ethnic groups who also adhere to the Islamic religion to be considered as Malay together with the original Malay inhabitants in the Malay Peninsula.