This study investigates mothers' expectations of and experiences with parental involvement during the transition to primary school. The participants were 20 mothers of children attending 10 kindergartens in Hong Kong. Individual interviews were conducted 3 months before and 3 months after their children entered their primary schools. As they had expected, after the transition to primary school, mothers needed to increase their involvement in homework supervision, while the time for play decreased. For parent-child reading, although mothers expected to be able to spend the same quantity of time reading with their child, they reported they had less time to do so because of the large number of formal learning tasks. The same mismatched expectation occurred in terms of social emotional guidance: mothers thought they would be able to guide children's social and interpersonal relationships but reported they had no time to do so because they were occupied with academic tasks. In terms of school involvement, mothers were strongly dissatisfied with the unexpected decrease in parent-school communication. Findings suggested the need to provide information about the expected load of home learning tasks to parents, offer resources to support parents' social and emotional coaching, and ensure the availability of effective parent-teacher communication channels.