Attempts to understand "subjectivity" have historically involved distinguishing the strengths of subjective methods (e.g., survey ratings from informants) from those of alternative methods (e.g., observational/performance-based tasks). Yet, a movement is underway in Psychology that considers the merits of "intersubjectivity": Understanding the space between two or more informant's subjective impressions of a common person or phenomenon. In mental health research, understanding differences between subjective impressions has less to do with informants' characteristics and more to do with the social environments or contexts germane to the people or phenomena examined. Our paper focuses on one relatively understudied social environment: the cultural context. We draw from seminal work on "psychological universals", as well as emerging work on cultural norms (i.e., "cultural tightness") to understand intersubjectivity effects through a cross-cultural lens. We report a meta-analysis of 314 studies of intersubjectivity effects in mental health, revealing that (a) this work involves independent research teams in over 30 countries, (b) informants rating a target person's mental health (e.g., parent and teacher ratings of a child's behavior) commonly provide diverging estimates of that person's mental health, and (c) greater convergence between subjective reports relates to a "tighter" or more norms-bound culture. Our paper illustrates strategies for understanding divergence between subjective reports. In particular, we highlight theoretical and methodological frameworks for examining patterns of divergence between subjective reports in relation to data from nonsubjective methods. We also describe how research on intersubjectivity informs efforts to improve the interpretability of subjective assessments in multiple sub-disciplines in Psychology. [This paper will be published in "Review of General Psychology."]