Narwhal (Monodon monoceros) responses to seismic survey ship noise were studied in Svalbard, Norway, during the summer of 2015 using satellite telemetry and audio recordings. Narwhals exhibited altered surfacing patterns and increased swimming speeds during the seismic trial compared with control periods, indicating behavioral disruption. Additionally, physiological changes, including elevated stress hormone levels and decreased reproductive hormone levels, provide further evidence of seismic noise impact. These findings contribute to our understanding of the potential effects of seismic surveys on narwhals and have important implications for the management of seismic surveys in areas inhabited by this species.