The study aims to describe overall gestational weight gain among Canadian women and to assess demographic, socio-economic, maternal, and pregnancy-related characteristics of gestational weight gain including uncovering the predictors above or below the range recommended by Health Canada. This study proceeds as a secondary data analysis of the Maternity Experiences Survey targeting women aged ≥15 years who had singleton live births in the Canadian provinces and territories in 2005/2006. The outcome variable considered was gestational weight gain within and outside the recommended guidelines. Various factors including demographic, socio-economic, maternal, and pregnancy-related characteristics were considered using multivariate statistical techniques. Bootstrapping was performed to account for the complex sampling design. One-third of women gained within the recommended guideline (32.6%), 18.7% gained below, and 48.7% gained above the recommended guideline. More than half of overweight (67.6%) or obese women (60.0%) gained above the guideline, and women with lower socio-economic status were more likely to gain above the recommended range. Conversely, being an immigrant, multiparous, and having health problems during pregnancy were associated with less weight gain during pregnancy as well as higher odds of gaining insufficient weight to meet the minimal weight gain guideline. In Canada, almost half of the women gain above the recommended guideline for weight gain in pregnancy. The findings may be useful to design interventions that target those at risk of gaining outside of the recommended guidelines and to reduce outcomes associated with inadequate or excessive gestational weight gain.