The potential toxic and pro-inflammatory effects of rod-shaped copper oxide (CuO) nanoparticles (NPs; 10 ± 3 nm in thickness and 74 ± 17 nm in length) were studied on N-hTERT keratinocytes and SZ95 sebocytes and on reconstructed human epidermis. Non-sonicated and sonicated CuO NPs induced similar cellular toxicity. The toxic effect of CuO NPs (non-sonicated and sonicated) was more pronounced in keratinocytes than in sebocytes. Pro-oxidant effects of CuO NPs were demonstrated by showing increase in the production of reactive oxygen species and decrease of cellular glutathione. In addition, DNA-binding activities suggested that redox-sensitive transcription factors Nrf2 and NF-κB were implicated in the response of keratinocytes to CuO NPs. Transcriptomic analysis showed an increase in the abundance of transcript species coding for pro-inflammatory interleukins (e.g. IL-8 and IL-1α) and chemokines. In reconstituted human epidermis exposed topically to raw CuO NPs, no effect on the integrity, viability and inflammatory response was noticed.