Background: Ozone (O₃) is a criteria air pollutant that is associated with numerous adverse health effects, including altered respiratory immune responses. Despite its deleterious health effects, possible epigenetic mechanisms underlying O₃-induced health effects remain understudied. MicroRNAs (miRNAs) are epigenetic regulators of genomic response to environmental insults and unstudied in relationship to O₃ inhalation exposure. Objectives: To test whether O₃ inhalation exposure significantly alters miRNA expression profiles within the human bronchial airways. Methods: Twenty healthy adult human volunteers were exposed to 0.4 ppm O₃ for two hours. Induced sputum samples were collected from each subject 48 hours pre-exposure and 6 hours post-exposure for evaluation of miRNA expression and markers of inflammation in the airways. Genome-wide miRNA expression profiles were evaluated using microarray analysis and in silico predicted mRNA targets of the O₃-responsive miRNAs were identified and validated against previously measured O₃-induced changes in mRNA targets. Biological network analysis was performed on the O₃-associated miRNAs and mRNA targets to reveal potential associated response signaling and functional enrichment. Results: Expression analysis of the sputum samples revealed that O3 exposure significantly increased the expression levels of 10 miRNAs, namely miR-132, miR-143, miR-145, miR-199a*, miR-199b-5p, miR-222, miR-223, miR-25, miR-424, and miR-582-5p. The miRNAs and their predicted targets were associated with a diverse range of biological functions and disease signatures, noted among them inflammation and immune-related disease. Conclusions: The present study shows that O₃ inhalation exposure disrupts select miRNA expression profiles that are associated with inflammatory and immune response signaling. These findings provide novel insight into epigenetic regulation of responses to O₃ exposure.