Purpose: Recent reports suggest that buprenorphine is being diverted and used nonmedically. However, no apparent studies have reported national-level data on buprenorphine diversion.Methods: Case report data were drawn from a quarterly survey of prescription drug diversion completed by a national sample of law enforcement and regulatory agencies who engage in drug diversion investigations. Quarterly rates of buprenorphine diversion per 100 000 population and 100 000 prescriptions dispensed were calculated for the period 2002 through 2019. Population-based diversion rates were also calculated by U.S. region.Results: In total, 9670 cases of diverted buprenorphine were reported across all 50 states and the District of Columbia during the study period. Buprenorphine diversion rates, per 100 000 population, were characterized by an accelerating increase over time; increases in diversion rates from 1st quarter 2002 through 4th quarter 2006 were not statistically significant, yet from 1st quarter 2007 through 4th quarter 2019, the rate of diversion cases increased by 0.0067 cases per 100 000 per quarter (p < 0.001). Buprenorphine diversion rates per 100 000 prescriptions dispensed indicated a gradual increase over time; from 3rd quarter 2010 through 4th quarter 2019, diversion rates showed a statistically significant increase of 0.28 cases (p = 0.037) per quarter on average. The Northeast was the only region that did not observe an increase in the average quarterly change in buprenorphine diversion rates after 2006.Conclusions: Findings from this study illustrate longitudinal national trends of increasing buprenorphine diversion. Continued systematic surveillance of this phenomenon is needed.