Security has been considered one of the most critical issues for managing IT resources in many organizations. Despite a growing interest and extensive research on security at various levels, little research has focused on the comparison of security knowledge levels between different cultures. The current study investigates and compares the security knowledge level between Korea and the U.S. Based on the literature review of spyware, Hofstede’s cultural dimensions, and security knowledge, this study identifies three constructs (i.e., security familiarity, spyware awareness, and spyware knowledge) to examine the difference of security knowledge levels between Korea and the U.S. Six hundred ninety-six respondents from Korea and the U.S. participated in the survey, and an in-depth analysis based on analysis of covariance (ANCOVA) was carried out. The results show that the levels of security familiarity, spyware awareness, and spyware knowledge are significantly lower in Korea than in the U.S., as expected. These findings present a significant association between national culture and security knowledge, and the degree of individualism (or collectivism) plays an especially critical role in the perception of security. A number of implications for academia and practitioners emerge. Limitations and future research directions are discussed in the conclusion.