The potential for nonnative, invasive plants to alter an ecosystem depends on species traits, ecosystem characteristics, and the effects of disturbances, including fire. This study identifies gaps in science-based knowledge about the relationships between fire and nonnative invasive plants in the United States. The literature was searched for information on 60 nonnative invasives. Information was synthesized and placed online in the Fire Effects Information System (FEIS, www.fs.fed.us/database/feis), and sources were tallied for topics considered crucial for understanding each species' relationship to fire. These tallies were analyzed to assess knowledge gaps. Fewer than half of the species examined had high-quality information on heat tolerance, postfire establishment, effects of varying fire regimes (severities, seasons, and intervals between burns), or long-term effects of fire. Information was generally available on biological and ecological characteristics relating to fire, although it was sometimes incomplete. Most information about species distribution used too coarse a scale or unsystematic observations, rendering it of little help in assessing invasiveness and invasibility of ecosystems, especially in regard to fire. Quantitative information on the impact of nonnative plants on native plant communities and long-term effects on ecosystems was sparse. Researchers can improve the knowledge available on nonnative invasive plants for managers by applying rigorous scientific methods and reporting the scope of the research, in both scientific papers and literature reviews. Managers can use this knowledge most effectively by applying scientific findings with caution appropriate to the scope of the research, monitoring treatment results over longer periods of time, and adapting management techniques as new information becomes available.