•The majority of children received more screen time during the pandemic; screen time increases were more pronounced in lower SES children.•Lower SES children were also more likely to experience a reduction in reading time than higher SES children.•Overall, children showed no detectable change in vocabulary growth during the pandemic when compared to their pre-pandemic age- and SES-matched peers.•Notably, however, a negative impact on vocabulary growth was observed in lower SES children in the vocabulary spurt age (19 to 29 months). The disruption caused by the COVID-19 pandemic has raised concerns about children’s development. Here, we examined the impact of the pandemic on Canadian infants’ and toddlers’ (N = 539) language development. Specifically, we assessed changes in 11- to 34-month-olds’ activities that are known to affect vocabulary development (i.e., screen and reading times). We also compared these children’s vocabulary sizes with those of 1365 children collected before the pandemic using standardized vocabulary assessments. Our results show that screen and reading times were most negatively affected in lower-income children. For vocabulary growth, no measurable change was detected in middle- and high-income children, but lower-income 19- to 29-month-olds fared worse during the pandemic than during pre-pandemic times. Moving forward, these data indicate that educators and policymakers should pay particular attention to children from families with lower socioeconomic status during times of crisis and stress.