Background/context: A growing body of evidence indicates that trustees link the boards of research universities to organizations in other fields. It is less clear whether these board characteristics indicate distinct university contexts with which particular activities would be associated. Research questions: We ask three questions. The first two are descriptive and focus attention on the changing characteristics of university boards: How do boards tie universities to other sectors of society? How has the composition of these ties changed over time? The third is inferential and attends to possible relationships between board characteristics and university activities over time: Are there relationships between board ties to external organizations and university activities? Research design: We answered our first two questions using descriptive analyses. We answered the third question using regression analyses, inclusive of fixed board-level effects, which estimated the within-unit association among board characteristics, control characteristics, and the dependent variables associated with activities of interest. Data collection and analysis: Our sample consisted of the 54 boards that oversaw members of the Association of American Universities. Data were compiled in 10-year increments between 1985 and 2015. Historical data on university boards were created using Standard and Poor’s Register of Corporations, Directors, and Executives and the Capital IQ Personal Intelligence database, both of which provided time-verified data about the affiliations of individual trustees at a given moment in time (e.g., 1985, 1995). We merged these data with information on university characteristics drawn from existing secondary data sources. Findings: Consistent with other analyses, sampled boards were increasingly connected to organizations in other fields over time. Connections grew especially rapidly between 1995 and 2015, with particularly notable growth in ties to the finance industry. In inferential analyses, the total number of ties to external organizations was associated with increases in total publications and with the share of publications in the biological sciences. Board characteristics were not associated with variation in other variables (e.g., endowment growth). Conclusions/recommendations: Our findings suggest that board characteristics are more likely to be associated with some university activities than others. It is less clear why this is the case. Our paper therefore lays important groundwork for future research on the ways in which individual trustees may directly coordinate, indirectly facilitate, or be selected because of their ties to particular external organizations.