It was investigated whether teachers' feedback skills to support students' self-regulated learning (SRL) can be improved by short-term video-based interventions and/or direct instructions that were adapted to a SRL framework. Forty pre-service and 40 in-service teachers were assigned to a video + instruction or an instruction-only condition. Highest improvements were expected for the combination of the two interventions. However, results indicated that functional feedback to support SRL benefited most from instruction-only, while the reduction of dysfunctional feedback was highest in the video + instruction condition. The findings have practical implications for the design of interventions to improve teachers' feedback skills.