Objective: The nonsuicidal self-injury (NSSI) disorder diagnostic criteria have been the focus of empirical study.However, Criterion A (i.e., required frequency and timeframe) has received relatively limited attention. The current study aimed to examine the relationship between past 12-month NSSI frequency and eight NSSI behavior features among individuals with past 12-month and 1-month NSSI.Method: Participants were 723 undergraduate students reporting at least 1 past 12-month NSSI act and completed online questionnaires. Decision trees and structural equation model trees were utilized to examine the relationship between NSSI frequency and behavior features.Results: Results highlight several potential subgroups: high (i.e., greater than 49 acts), moderate-to-high (i.e., 19-48 acts), low-to-moderate (i.e., 7-18 acts), and low (i.e., fewer than 6 acts) frequency subgroups.Conclusions: Findings suggest that increasing the NSSI disorder criterion A frequency cutoff or requiring at least one past month NSSI act may better demarcate individuals with more severe NSSI behavior. K E Y W O R D S exploratory data mining, nonsuicidal self-injury frequency, nonsuicidal self-injury severity, NSSI disorder