This book documents modern Baba Malay, a critically endangered Austronesian-based contact language with a Sinitic substrate. Formed via intermarriage between Hokkien-speaking male traders and indigenous women in the Malay Peninsula, the language has less than 1,000 speakers in Singapore and less than 1,000 speakers in Malacca, Malaysia. This volume fills a gap for reference grammars of contact languages in general. Reference grammars written on contact languages are rare, and much rarer is a reference grammar written about a critically endangered Austronesian-based contact language. The reference grammar, which aims to be useful to linguists and general readers interested in Baba Malay, describes the language’s sociohistorical background, its circumstances of endangerment, and provides information regarding the phonology, parts of speech, and syntax of Baba Malay as spoken in Singapore. A chapter that differentiates this variety from that spoken in Malacca is also included. The grammar demonstrates that the nature of Baba Malay is highly systematic, and not altogether simple, providing structural information for those who are interested in the typology of contact languages.