This study had three objectives: (a) to compare undergraduates from four Arab countries on self-esteem, (b) to explore the sex-related differences in self-esteem in these four Arab countries, and (c) to examine the association of self-esteem with both per-capita income and unemployment rate. Four samples of 2,643 students were recruited from Egypt (n = 576), Kuwait (n = 674), Lebanon (n = 826), and Oman (n = 567). They responded to the Arabic version of the Rosenberg Self-Esteem Scale. Kuwaiti and Omani men had a significantly higher mean score on self-esteem than did Egyptian and Lebanese men. Egyptian women scored significantly lower than the Omani women, but the effect size was small. Regarding the sex-related differences in self-esteem, Kuwaiti men had a significantly higher mean score than did their female peers, but the effect size was small, whereas there were no significant sex differences in the other samples. The sex-related difference in self-esteem is a controversial result and it may not be replicable in different countries. It was suggested that self-esteem is associated with high per-capita income and low unemployment rate.