This article explores whether Sunday is a day off in Japan. While there are laws requiring employers to give their employees at least one day off per week, it can be any day and not necessarily Sunday. However, many companies still give their employees Sunday off as it has become the de facto standard for weekends in Japan. The article also examines the history of Sunday as a day off in Japan, the impact of religion on Sunday observance, the role of unions in protecting employee rights, and the challenges faced by working parents. It concludes that improving work-life balance in Japan will require a multi-faceted approach involving government policies, employer initiatives, and cultural change.