Gender differences in communication styles have been observed in subjects of all ages, in many cultures. This study was designed to see whether such gender differences persist in happily married couples. Observers coded the nonverbal behaviors of 40 happily married US couples who were videotaped discussing commitment in marriage. Although these couples showed no significant sex differences in marital satisfaction (as measured by the MARQ of Russell and Wells) or in verbal statements regarding commitment, robust sex differences in the following nonverbal behaviors emerged: smiling, laughing, and average length of look at spouse (t-test for matched pairs, p<0.01). Wives looked significantly longer, as if listening attentively; husbands used shorter glances at wives, suggesting a monitoring function. Results were consistent across age and length of marriage. Experimenter effects were seen, in that husbands were more likely to speak first with a male experimenter, and discussions went on longer with a female experimenter.