The perception that a partner is supportive, tied to beneficial relational and personal outcomes, may be shaped by reality (the partner's actual support) but is often also biased. Using T. V. West and D. A. Kenny's (2011) truth‐and‐bias model, the balance between truth and one bias type—the tendency to maintain perceived mutuality by projecting one's own supportiveness onto one's partner—was examined. It was hypothesized that this balance will be altered by the behavior's psychological significance and by the scope of the behavior being judged. In a 35‐day diary, 80 couples reported perceived and provided emotional/practical support. Participants' judgments included less biased projection when they addressed behaviors of lower emotional significance or greater contextual specificity.