In three consecutive studies, the current dissertation investigated the roles of proactive and reactive sensitivity in adult romantic relationships from a cross-cultural perspective and the roles of attachment orientations in understanding potential differences in partner/spouse sensitivity. In the first study, the psychometric properties of partner sensitivity and perceived partner sensitivity measures were tested on married participants in Turkey (N = 297). Although two types of sensitivity were obtained, there was a high correlation between the subscales that called for further studies. In the second study, the sensitivity measure was converted into a binary forced-choice scenario-based scale, and thus, categorical sensitivity variables were obtained. A dyadic study was conducted with married couples in Turkey (N = 112 couples). The psychometric quality of the revised scale was satisfactory, and proactive sensitivity was positively associated with the indicators of relationship functioning. Wives with high attachment avoidance and husbands with high attachment anxiety perceived their spouses‟ proactive sensitivity negatively. Wives‟ attachment avoidance also predicted husbands‟ perceived proactive sensitivity. In the third study, a cross-cultural study was conducted with married/cohabiting individuals in Turkey (N = 201) and the United States (N = 224). The measure was partially invariant across the samples. Contrary to expectations, reactive sensitivity was the predominant pattern in Turkey, while both proactive and reactive sensitivity were common in the US. As expected, women were perceived as more proactively sensitive than men. Attachment avoidance was the major predictor of both types of sensitivity in Turkey and proactive sensitivity in the US. Cultural implications of the findings and suggestions for further research were discussed.