The 1921 Canadian Census is exploited to examine the labour market attainment of Canadian women. Acknowledging the general context of Catholic and Protestant divide and the tensions between francophones and anglophones during the WWI, special attention is paid to the influences of religious affiliation, ethnicity, and linguistic proficiency. Working urban women, overwhelmingly unmarried, are found to earn between 68 and 29% less than their male counterparts, depending on occupation and religio-linguistic group. The gender earnings gap is found to be the largest among francophone Catholics. When the sample is restricted to unmarried urban women, francophone Catholic females are found at a large disadvantage compared with anglophone Catholic and Protestant females. Bilingual Catholic women, mostly of French Canadian ethnicity, were the second lowest earning group in Canada of 1921. Bilingual Protestant women, on the other hand, are found to have had the most favourable labour market outcomes. The cumulative weight of the results indicates that among religious affiliation, ethnicity, and linguistic proficiency, ethnicity had exercised the strongest influence on the labour market attainment of Canadian women at that time.