In recognising sexuality education as a socially divisive topic in Canada and other national contexts, this article addresses the issues encountered at the elementary level in a multi-ethnic context regarding the implementation of the 2018 Quebec's sexuality education program, through the lens of the ethnic boundaries framework. The findings come from the analysis of virtual asynchronous written focus groups conducted with migrant parents and elementary school SE educators in Montreal. The analysis highlights the (re)production of an ethnic boundary between the school and migrant parents and its impact on actors' experience of SE in school. The discussion points out avenues for improving the SE pedagogy among other things, in terms of culturally responsible pedagogy and to recognise the legitimacy of migrant parents as partners of the school.