This study investigated the effect of sow vaccination against virulent strains of Glaesserella parasuis on the nasal microbiota of piglets. Nasal swabs were taken from piglets at 15 days old from sows that were vaccinated (vs-P) or unvaccinated controls (cs-P). 16S rRNA sequencing showed the vs-P piglets had lower G. parasuis levels and diversity in their microbiota. Analysis revealed differences in alpha and beta diversity between the vs-P and cs-P groups. Correlation network analysis also showed differences between the groups, with the cs-P network having more nodes and connections. Key nodes in the cs-P network were absent in the vs-P