Objectives: The effect of the combination of working hours and working time mismatch on depression is unknown. This study was undertaken to confirm the relationship between working time mismatch and depression with respect to hours worked. Material and Methods: The data of 45 514 adult workers that participated in the 6th Korean Working Conditions Survey (KWCS‐VI 2020) were reviewed. Depression was defined using the World Health Organization 5 Well-Being Index (WHO-5) cut-off score of 50. Working time mismatch was defined as a difference between actual and desired working hours. To identify associations between working hour mismatch and depression according to weekly hours worked, stratification analysis was conducted by dividing the study subjects into 3 groups based on actual hours worked weekly (<40 h, 40–<52 h, or ≥52 h). Multiple logistic regression analysis adjusted for potential confounders was performed to calculate odds ratios of depression. Results: In the <40 h, 40–<52 h, and ≥52 h groups, the odds ratios (OR) of working more hours than desired were 1.51, 95% CI: 1.20–1.92 (<40 h), 1.70, 95% CI: 1.58–1.84 (40–<52 h), and 1.55, 95% CI: 1.41–1.69 (≥52 h), respectively, compared to a matched actual versus desired working hours group (the matched group). On the other hand, the odds ratios of working fewer hours than desired were 1.17, 95% CI: 1.07–1.27 (<40 h), 1.38, 95% CI: 1.20–1.60 (40–<52 h), and 1.98, 95% CI: 1.24–3.17 (≥52 h), respectively. The risk of depression was found to increase significantly with working time mismatch within all 3 working hour groups. Conclusions: Working time mismatch increases the risk of worker depression regardless of hours worked. Int J Occup Med Environ Health. 2023;36(6):788–97