The studies reported in this paper had two purposes: (1) the construction of a measure of jealousy and (2) the use of this measure to test some of the prevalent beliefs concerning jealousy, thus providing construct validity data for the scale and expanding empirical understanding of jealousy. Using the rational approach to test construction, a 28-item test was constructed. It was hypothesized that this scale would correlate positively with romantic love, insecurity, and low-self-esteem, and negatively with separate identities. It was also hypothesized that it would not correlate with liking. These relationships were found except for the positive correlations between jealousy and insecurity for men, jealousy and low self-esteem for both sexes. It was concluded that enough evidence of construct validity was found to warrant further use of the scale for research purposes. It was suggested that open marriage relationships be based primarily on liking rather than romantic love so as to avoid jealousy. (Author)