Previous studies showed associations of sedentary behavior with cardiovascular risks, independent of moderate-to-vigorous physical activity. However, few studies have focused on Japanese workers. This study examined the joint association of television viewing time (TV) and walking time (WT) with overweight/obesity among Japanese municipal office workers. A cross-sectional survey collected height, weight, and time spent in TV and WT from 2,175 Japanese workers, aged 22-62 years-old, by self-administered questionnaire. Participants were classified into four categories according to TV (dichotomized into long (>2 hours/day) and short (≤2 hours/day) by the median) and WT (dichotomized into long (≥30 minutes/day) and short (<30 minutes/day) by 30 minutes/day). Odds ratios (OR) for overweight/obesity (body mass index ≥25kg/m²) were calculated according to the four TV/WT categories, adjusted for potential confounders. Overweight/obesity accounted for 30.5% of men and 15.3% of women. Among men, the adjusted ORs (95% CI) of overweight/obesity were 1.14 (0.76, 1.70) for long TV/long WT, 1.13 (0.77, 1.65) for short TV/short WT, and 0.97 (0.67, 1.42) for short TV/long WT, compared with the reference category (long TV/short WT). Among women, the adjusted ORs (95% CI) were 0.70 (0.39, 1.13) for long TV/long WT, 0.55 (0.33, 0.94) for short TV/short WT, and 0.54 (0.33, 0.89) for short TV/long WT. Spending a long time watching television was associated with a higher risk of being obese in Japanese female municipal office workers, independent of WT. Further studies using prospective designs are warranted to develop an effective weight control program for Japanese workers.