Highlights Reappraisal and suppression were examined for EEG alpha band power. Reappraisal was positively correlated with alpha power of the frontal region. Suppression score was not correlated with alpha band power of all channels. The frontal alpha band power is correlated with reappraisal only in females. Abstract Purpose: Cognitive reappraisal and expressive suppression are major emotion regulation strategies in adjusting to daily life. We hypothesized that cognitive reappraisal and expressive suppression would be related to alpha band power in brain regions. Materials and Methods: Fifty-nine subjects were examined with the Emotion Regulation Questionnaire, and their EEG band power during eyes closed at rest was recorded on the same day. Results: Reappraisal was positively correlated with alpha power of the frontal region in entire group (males and females). In males (n = 29), reappraisal was negatively correlated with beta power of left temporal region. In females (n = 30), reappraisal was positively correlated with alpha power of frontal and central regions, education years, and age. However, the suppression score was not correlated with any of the band powers. No significant differences in alpha power and delta power were observed in any of brain regions between males and females. In beta power, significant differences were observed between males and females in central, parietal, right temporal, and occipital regions, and marginally significant differences were observed in frontal and left temporal regions. In theta power, significant differences were observed between males and females in occipital region, and marginally significant differences were observed in central and parietal regions. Conclusions: These results indicate the tendency for reappraisal could occur more in a relaxed mental state and increases with learning and life experience in females.