Objectives North Koreans have been facing chronic food shortages and malnutrition. This study examined the nutritional status of North Koreans and the perceptions of South Korean adults regarding their nutritional status. Methods The nutritional status was examined using nutritional indicators for the general population, children, and reproductive-aged women in North Korea. An online survey was conducted among 1,000 South Korean adults aged 19–69 years to investigate their perceptions regarding the nutritional status of North Koreans. Results Although the nutritional status of children in North Korea has consistently improved, significant progress in the general population and reproductive-aged women in the country remains elusive. The prevalence of malnutrition among North Korean children has decreased to a level that is not considered severe based on international standards, although it shows a substantial difference from that among South Korean children. The prevalence of undernourishment and food insecurity in North Korea remains over 40%. South Korean adults perceive the nutritional status of North Koreans as being more severe than it is in reality. Notably, a significant inconsistency exists between the perceived and actual nutritional status of North Korean children, with over 95% of South Korean adults perceiving North Korean children’s malnutrition as being more severe than it actually is. Moreover, South Korean adults in their 20s to 40s tended to perceive the nutritional status of North Koreans as being more severe than those in their 50s to 60s did. Conclusions The nutritional status of North Koreans is a matter of concern. The disparity between South Koreans’ perceptions of the nutritional status of North Koreans and the actual status highlights the need for accurate information dissemination to effectively address malnutrition in North Korea. These efforts could be instrumental in enhancing public awareness and fostering social consensus on food aid and nutritional support programs for North Korea.