Aim <p>This study aims to add to the growing evidence base on trauma-informed practice training, examining the impacts of five training programmes delivered to a range of professionals. The study also explores whether the impacts of the training programmes differ by mode of delivery, and whether there are differences in baseline trauma-informed knowledge and attitudes by sociodemographic factors.</p> Subject and methods <p>Across each of five trauma-informed practice training programmes, participants completed baseline and post-training surveys, including measures on sociodemographic characteristics and trauma-informed knowledge and attitudes, utilising two of the five subscales of the Survey for Trauma-Informed Systems Change.</p> Results <p>Analyses indicated baseline differences in individual-level and system-wide trauma-informed knowledge and attitudes by participant sociodemographic factors—particularly by years of working experience and organisation type. All training programmes, including one tailored towards leadership staff, showed significant improvements from baseline to post-training in participants’ trauma-informed knowledge and attitudes; however, some of the training programmes had significantly more positive levels of impact than others.</p> Conclusion <p>This study suggests that while a suite of different trauma-informed training programmes are effective in improving multi-agency trainees’ trauma-informed knowledge and attitudes, training programmes with certain delivery methods may be more impactful than others. The study also found that there may be important sociodemographic differences in individuals’ baseline levels of trauma-informed knowledge and attitudes. Findings may have implications in terms of how best to deliver trauma-informed training programmes, where best to target resources to improve trauma-informed practices, and developing collaborative multi-agency approaches towards trauma-informed working.</p>