Carstairs Douglas was a Scottish missionary, remembered chiefly for his writings concerning the Hokkien language of Southern Min in Southern Fujian, in particular his Chinese–English Dictionary of the Vernacular or Spoken Language of Amoy.

Pe̍h-ōe-jī, sometimes known as Church Romanization, is an orthography used to write variants of Hokkien Southern Min, particularly Taiwanese and Amoy Hokkien, and it is widely employed as one of the writing systems for Southern Min. During its peak, it had hundreds of thousands of readers.