Jealousy has been defined as a negative response to the actual, imagined, or expected emotional, and particularly sexual, involvement of one’s partner with someone else (e.g., Buunk, 1991), and has been conceptualized as a multidimensional phenomenon (e.g., Sharpsteen, 1991). In line with these perspectives, our purpose was to develop separate scales for three types of jealousy. First, reactive jealousy refers to the degree of upset people experience if their partner would engage in a number of intimate behaviors with a third person. Second, preventive jealousy (also referred to as possessive jealousy or mate guarding; Buunk & Castro Solano, 2012) concerns an extreme preoccupation with even slight indications of interest on the part of one’s partner in a third person, expressed through considerable efforts to prevent contact of the partner with individuals of the opposite sex. A similar phenomenon has been labelled behavioral jealousy by Pfeiffer and Wong (1989). Third, anxious jealousy refers to an obsessive focus upon the mere possibility of the sexual and emotional involvement of one’s partner with someone else. This implies an active cognitive process in which one generates images of the partner becoming sexually involved with someone else, which leads to more or less obsessive anxiety, upset, suspiciousness, and worrying (similar to cognitive jealousy, as distinguished by Pfeiffer & Wong, 1989).