We explore the evolution and determinants of attitudes towards immigration in Canada, utilizing Canadian Election Studies surveys from 1988 to 2019. Our analysis indicates a notable trend: a consistent decrease in anti-immigrant sentiments until the mid-2000s, followed by a shift around 2008 towards gradually more negative attitudes towards immigration. To better understand the factors influencing these attitudes, we examine a comprehensive set of variables. While economic factors seem to have some association with these attitudes, our findings more significantly underscore the role of group-level socio-psychological factors. Additionally, our analysis identifies an emerging polarization along political party lines beginning around 2006. Assessing the relative impact of these factors, our analysis suggests that political party identification has become increasingly significant in influencing attitudes toward immigration.