As organizational structures become flatter and job characteristics grow increasingly complex, the importance of close interactions among members is being increasingly emphasized. Within this trend, the importance of helping behavior among coworkers has also been progressively highlighted. Generally, helping behavior has been understood to positively influence group and organizational performance by fostering cooperative relationships among colleagues. However, recent research has raised the argument that even identical helping behavior can yield opposite outcomes depending on how the recipient interprets the behavioral intent. In this study, to identify the factors that influence the interpretation of coworkers' helping behavior, we examined the effects of characteristics of both the actor (help provider) and the rater (help recipient) on the evaluation of helping behavior within dyadic peer relationships. Specifically, first, by examining the characteristics of helping behavior that distinguish it from task performance behavior, we discussed the implications of these characteristics for explaining the helping behavior evaluation process. Second, we tested the moderating effects of the actor's ability to modify self-presentation and the rater's self-enhancement motives as moderating variables in the relationship between a coworker's helping behavior and the rater's recognition of it as organizational citizenship behavior (OCB-I). The empirical results supported all hypotheses. When help was provided at low levels, actors with high ability to modify self-presentation were evaluated as engaging in more organizational citizenship behavior than those with low ability. That is, individuals with high ability to modify self-presentation have the capacity to impressively convey their help provision to others even when providing little help, and thus receive favorable OCB evaluations from coworkers. Additionally, raters with strong self-enhancement motives were less inclined to evaluate coworkers' helping behavior as organizational citizenship behavior compared to raters with weak self-enhancement motives. These results can be explained by the attributional projection effect: raters with stronger self-enhancement motives project their self-information related to helping behavior—specifically, the awareness that helping behavior can be instrumentally used for purposes such as image enhancement—onto the evaluation process. Through these empirical findings, this study contributes to the understanding of helping behavior interpretation in three ways. First, by demonstrating that the rater's cognitive process influences the evaluation of helping behavior, similar to personnel appraisals, this study expanded the research domain on helping behavior interpretation. Second, by showing that both rater and actor characteristics influence helping behavior evaluation, this study provided an in-depth examination of helping behavior interpretation in dyadic relationships. Third, this study examined helping behavior in peer relationships, which has received insufficient research attention in the organizational behavior field relative to its importance.