James Alfred Wanklyn (18 February 1834 – 19 July 1906) was a nineteenth-century English chemist who is remember today chiefly for his "ammonia method" of determining water quality and for his fierce arguments with those, such as Edward Frankland, who opposed him over matters related to water analysis. Wanklyn was born in Ashton-under-Lyne and died in New Malden. He worked with Frankland, Robert Bunsen, and Lyon Playfair. He was Professor of Chemistry at the London Institution after 1864, and many of his papers were published from that institution.