The purpose of this study is to examine how daylight exposure affects the health and well-being of office workers. Sleep actigraphy and health and well-being related survey data were the main dependent variables in this study. Research samples were composed of participants from the United States and South Korea, each set of workers divided into those having daylight at their workplaces and those without. Fifty participants in total wore for two weeks actiwatches equipped with light sensors to measure sleep quality and exposure to ambient light levels. Additional health and well-being measurements were taken using well established survey instruments such as the SF-36 for general and mental health, and the Pittsburg Sleep Quality Index (PSQI) for sleep. In order to estimate the levels of daylight participants were exposed to, computer simulation was used to generate the total annual daylight levels in each participant’s office. Our results seem to indicate that working in daylit office spaces would lead to higher sleep quality and higher scores of the health and well-being scales compared to those who do not work under daylight conditions. Our findings indicate that it is important to provide and maintain significant daylight levels at the workplace. Consequently, in terms of architectural design, building orientation, building dimensions, and the size and height of windows should be taken into consideration to optimize or maximize daylight exposure.