Despite remarkable growth and relevance of the 340B Drug Pricing Program to current health care practice and policy debate, academic literature examining 340B has lagged. The objectives of this scoping review were to summarize i) common research questions published about 340B, ii) what is empirically known about 340B and its implications, and iii) remaining knowledge gaps, all organized in a way that is informative to practitioners, researchers, and decision makers. We conducted a scoping review of the peer-reviewed, empirical 340B literature (database inception to March 2023). We categorized studies by suitability of their design for internal validity, type of covered entity studied, and motivation-by-scope category. The final yield included 44 peer-reviewed, empirical studies published between 2003 and 2023. We identified 15 frequently asked research questions in the literature, across 6 categories of inquiry-motivation (margin or mission) and scope (external, covered entity, and care delivery interface). Literature with greatest internal validity leaned toward evidence of margin-motivated behavior at the external environment and covered entity levels, with inconsistent findings supporting mission-motivated behavior at these levels; this was particularly the case among participating disproportionate share hospitals (DSHs). However, included case studies were unanimous in demonstrating positive effects of the 340B program for carrying out a provider's safety net mission. In our scoping review of the 340B program, the highest-quality evidence indicates nonprofit, DSHs may be using the 340B program in margin-motivated ways, with inconsistent evidence for increased safety net engagement; however, this finding is not consistent across other hospital types and public health clinics, which face different incentive structures and reporting requirements. Future studies should examine heterogeneity by covered entity types (i.e., hospitals vs. public health clinics), characteristics, and time period of 340B enrollment. Our findings provide additional context to current health policy discussion regarding the 340B program.