This paper evaluates the sociocultural integration of newcomers, paying special attention to language proficiency while taking into account the importance of the assimilation, cultural fit, and social network perspectives. Analyses are based on administrative data collected by the YMCA of South Western Ontario regarding 2,493 of their clients. Results reveal that newcomers’ length of residency, ethnic origin, and social networks play a significant role in the sociocultural integration of newcomers. The longer the newcomers have resided in Canada, the higher their level of sociocultural integration. Non-Europeans displayed a lower level of sociocultural integration than Europeans. However, the most important predictor of sociocultural integration was language proficiency. Not only did language proficiency have a strong and independent effect, but it also tended to level out differences in sociocultural integration of those who had resided in Canada for a short period compared to those living in Canada for a longer period. Similarly, language proficiency decreased sociocultural integration differences between Europeans and ethnic minority newcomers. The policy implications of the results are discussed.