This study explores predictors of scientific institutes and centers’ self-reported perceived public engagement successfulness using data from five countries, including Germany, Italy, the Netherlands, the United Kingdom, and the United States. Results show that a history of engagement activity, access to a dedicated public engagement employee, and an engagement policy are all small but potentially useful correlates of perceived engagement success. Similarly, research units where the respondent indicated that they did not think the public was interested in engagement reported relatively less public engagement successfulness. The findings are consistent with Excellent Theory’s emphasis on the importance of organizational factors in fostering engagement quality. There were few consistent differences by country or field and also few differences as a function of organizational respondents’ perceptions of the public.