||We carried out field measurements to determine the contribution of advertisement and decorative lighting to local light pollution in Seoul. We used the lighting limits set by the “Light Pollution Prevention Act”, which regulates light pollution, as measuring criteria. Our results show that both advertisement and decorative lighting are significant contributors to local light pollution in Seoul. Thirty percent of advertisement lighting measured in our study areas exceeded the legal limits. Moreover, we found that certain types of advertisement lighting are more likely to cause light pollution than the others. In addition, 73% of the decorative lighting found in our sample areas exceeded the legal limits. Based on our findings, we suggest that local light pollution policies establish a curfew time when all advertisement and decorative lighting must be completely turned off. Such an approach is essential in reducing lighting levels in outdoor environments. Furthermore, it lessens the burden on law enforcement personnel, who otherwise must ensure that advertisement and decorative lighting levels are kept within the legal limits. In light of the ongoing debate over the role of lighting in public well-being and the sustainability of cities, the present study provides a discussion on the status and management policy of light pollution caused by advertisement and decorative lighting.