Background: Staphylococcus aureus (S. aureus) carriage and sensitization to S. aureus enterotoxins (SEs) have been associated with allergic diseases. From the Tromso Study Fit Futures 2, we have previously shown an association between S. aureus carriage and severe allergic disease and allergic multimorbidity. However, the role of S. aureus carriage and SE sensitization on allergic multimorbidity and allergic sensitization is unclear. Objective: To study associations of both nasal S. aureus carriage and SE sensitization to allergic disease and allergic sensitization. Methods: A cross-sectional study of a school-based cohort in late adolescence (aged 18-19 years: The Tromso Study Fit Futures 2). Self-reported allergic diseases were assessed using the Mechanisms of the Development of ALLergy questionnaire (MeDALL). Participants were tested for nasal S. aureus carriage, serum total IgE and specific IgE to SEs, and food and inhalant allergens. Results: A total of 868 participants were studied. Sensitization to at least one food or inhalant allergen was found in 319 of 765 (41.7%), and to at least one SE in 173 of 656 (26.2%) participants. SE sensitization, but not S. aureus carriage, was associated with poly-sensitization to food and inhalant allergens. SE-sensitized participants had higher median specific IgE to inhalant allergens (41.4 kUA/L, IQR 10.1-118.4) compared to non-SE-sensitized participants (18.0 kU(A)/L, IQR 5.5-48.6, P=.004), but not to food allergens. SE sensitization was associated with allergic multimorbidity. Conclusion: Sensitization to SEs may play a role in the development of allergen poly-sensitization and allergic multimorbidity.