This study examined the interplay between behavioral inhibition/activation systems (BIS/BAS) sensitivity, attachment insecurity (i.e., anxiety and avoidance), and Big Five personality traits in predicting sensory processing sensitivity (SPS). We have specifically tested three alternative theoretical models to explain the process through which BIS/BAS sensitivity link to SPS; unique effects of attachment dimensions and personality traits, as well as moderating and mediating role of these variables. Participants (N=494) completed the highly sensitive Person scale, BIS/BAS scales, experiences in close relationships-revised scale, and big five inventory. The findings revealed the complex role of attachment dimensions and personality traits on SPS. Attachment avoidance, but not attachment anxiety, moderated the effect of BIS activity on SPS indicating that, compared to those with high BIS sensitivity, those with low levels of both BIS and attachment avoidance reported lower level of SPS. Attachment anxiety, neuroticism, extraversion, and openness partially mediated the effects of BIS on SPS. Conceptual implications of the findings and suggestions for future research are discussed.