There has been substantial literature on boundary excursions in clinician-patient relationships; however, very little empirical research exists. Even less information exists on how perceptions of this issue might differ across cultures. Prior to this study, empirical data on various kinds of boundary excursions were collected in different cultural contexts. First, clinicians from the US. and Brazil were asked to rate 173 boundary excursions for both their perceived harmfulness and their professional unacceptability (Miller et al., 2006). In a second study, colleagues from Qatar administered a slightly modified version to mental health care professional staff of a hospital in Doha, Qatar (Ghuloum et al., 2011). In this paper, the results of these two separate studies are compared. The results showed some similarities and some differences in perceptions of the boundary behaviors. For example, both sets of cultures seem to agree that certain behaviors are seriously harmful and/or professionally unacceptable. These behaviors include some frankly sexual behavior, such as having sexual intercourse with a patient, as well as behavior related to doing business with the patient, and some disclosing behavior. There are also significant cultural differences in perceptions of how harmful some of the behaviors are. Qatari practitioners seemed to rate certain behaviors that within therapy mix disclosing or personal behavior with therapy as more harmful, but behaviors that involved interacting with patients outside of therapy as less serious. A factor analysis suggested that participants in U.S./Brazil saw a much larger number of behaviors as making up a set of Core Boundary Violations, whereas Qatari respondents separated sexual behaviors from others. Finally, a Rasch analysis showed that both cultures perceived a continuum of boundary behaviors, from those that are least harmful or unprofessional to those that are highly harmful or unprofessional. One interpretation is that cultural factors may be most influential on those kinds of behaviors that are perceived as relatively less serious. Implications for training and supervision are also discussed. (C) 2012 Elsevier Ltd. All rights reserved.