BackgroundTrauma-informed care (TIC) is growing in medical education as healthcare systems recognize trauma’s impact on health outcomes. TIC acknowledges and responds to the effects of trauma on physical, psychological, and emotional health. As TIC trainings are developed and delivered to healthcare professionals across the learner continuum, curricula need evaluation beyond learner satisfaction and knowledge to better assess changes in skills. We developed the Gap Kalamazoo Communication Skills Assessment Form for Trauma-Informed Care (GKCSAF-TIC) to evaluate pediatric trainees' communication skills in TIC. ObjectiveDescribe the development and validity evidence of the GKCSAF-TIC in assessing pediatric residents' TIC skills during standardized patient encounters. MethodsWe developed and implemented the TIC communication skills assessment tool in a one-year prospective cohort study involving pediatric residents. We conducted simulated patient encounters conducted before and after TIC training, with two pediatric faculty attendings assessing each encounter. We gathered validity evidence using Messick’s framework, focusing on content, response process, internal structure, and relationship with other variables. ResultsWe analyzed 57 standardized patient encounters with 33 pediatric interns, including 23 pre-post matched pairs. The development process and rater training supported content and response process validity. Internal consistency, measured by Cronbach’s alpha, ranged from 0.93 to 0.96, while inter-rater reliability, measured by intraclass correlations, ranged from 0.80 to 0.83. There was a significant improvement in scores from pre-training to post-training (3.7/5 to 4.05/5; p < 0.05). ConclusionThe GKCSAF-TIC demonstrated strong preliminary validity and offers educators a valuable means to assess and provide formative feedback to pediatric trainees about TIC. What’s New?Pediatric trainees are learning about trauma-informed care and need formative feedback on their practice of TIC in the clinical setting. The GKCSAF-TIC can be used to evaluate and provide formative feedback to trainees about their communication skills in providing trauma-informed care.