BackgroundGrowing concerns about harmful sexual behaviour (HSB) experienced and exhibited by children and young people has resulted in a demand for training programs for frontline workers. However, HSB professional development initiatives must contend with various challenges and competing demands. ObjectiveThis study evaluated workshops and webinars as professional development tools to upskill frontline workers on preventing, identifying, and responding to HSB. Particularly, whether these platforms met the needs of the workforce; increased professionals’ perceived knowledge, confidence, competence, and actual knowledge, in what ways; and whether the training was subsequently applied in practice to identify and respond to HSB. Participantsand Setting: Surveys were issued pre- and post-workshop/webinar training to measure changes in frontline workers’ perceived knowledge, confidence, competence, and actual knowledge, to identify and respond to HSB (n = 638 pre- and n = 418 post-workshop respondents; n = 473 pre- and n = 419 post-webinar; n = 3 workshop and n = 27 webinar 12-month follow-up). MethodsQuantitative (paired sample t-tests, one-way ANOVA, and independent sample t-tests) and qualitative thematic analyses from pre- and post-workshop/webinar survey responses were conducted. FindingsFindings tentatively indicate workshops and webinars met the needs of participants and, overall, were effective in increasing perceived knowledge, confidence, competence, and actual knowledge. Despite a smaller 12-month follow-up sample, knowledge and skills learned from training were subsequently applied in practice to identify and respond to HSB. ConclusionThere is promising value in workshops and webinars as professional development tools for upskilling a diverse, and geographically dispersed, workforce.