<p>Conduct problems emerge early in childhood and can lead to severe maladjustment across the lifespan if not appropriately managed. These problems are highly prevalent in school settings, yet educators reportedly struggle to manage them. When conduct problems co-occur with callous-unemotional (CU) traits, risk for severe, persistent disruptive behavior and academic underachievement increases, necessitating targeted management strategies. The current study evaluated a brief internet-delivered positive classroom management training (iPCMT), informed by the principles and strategies of home- and school-implemented parent management training programs, including those targeting CU traits. Of the 275 elementary school educators that were randomly assigned to either the Immediate-iPCMT condition (<i>n</i> = 137) or the Waitlist Control condition (<i>n</i> = 138), 228 educators (Mean age = 40.22, 86.1% female-identifying) were included in the final intent-to-treat analyses. At post-intervention, the final educator sample showed significant improvement in their knowledge of conduct problems, but this gain was not maintained for the 28.1% of educators who participated in the 5-week follow-up. Educators who nominated a disruptive student also reported significant decreases in student-educator conflict, but no significant improvements in student-educator closeness, student conduct problems, or student CU traits. Acceptability and feasibility ratings among participants who completed iPCMT were high, but there was a high overall attrition rate. Although iPCMT requires further refinement to increase participant retention and effectiveness, it may serve as a starting point for further research on developing educators’ knowledge of heterogeneous conduct problems. More research is also needed to test the effects of iPCMT in the longer-term, with multi-method outcome measures.</p>