Defeating the opioid crisis will require diverse partnerships and collaborations, as well as research and programming to protect responding officers from physical and mental health risks of encountering the tragic effects of opioids on the streets every day. This article, based on the grantee report Law Enforcement Efforts to Fight the Opioid Crisis: Convening Police Leaders, Multidisciplinary Partners, and Researchers to Identify Promising Practices and to Inform a Research Agenda (2019), details a two-day National Institute of Justice event that included law enforcement experts, government and community stakeholders, and public health professionals to promote diverse partnerships and collaborations in response to the opioid epidemic. For law enforcement, overcoming the opioid crisis will mean gaining a deep, science-driven understanding of its dimensions. NIJ gathered a cross section of experts to identify priority research needs and action items. A working group of law enforcement leaders and other experts, called by the National Institute of Justice (NIJ), has spotlighted effective practices and identified priority research needs as well as opioid-related challenges. The expert group isolated 13 high-priority needs, most of which are not yet fully understood, requiring more research. Four of those needs are deemed critical and require immediate implementation: 1. Use of medication-assisted and other treatment modes in institutional and community corrections; 2. Same-day access to treatment with a medication-first model of care; 3. The use of syndromic surveillance or "sentinel indicators" to spot or predict spikes in overdoses, the appearance of new opioids, or new drug crises; and 4. Mental health intervention for law enforcement officers affected by stress from responding to the opioid crisis.