As development of research ethics competencies is in the focus in higher education (HE) institutions, it is crucial to understand how to support the learning process during such training. While there is plenty of research on how to scaffold children's learning of cognitive skills, there is limited knowledge on how to enhance collaborative case-based learning of research ethics competencies in HE contexts. Our aim was to identify whether, how and when scaffolding is needed with various expertise levels to support development of ethics competencies. To identify and evaluate scaffolding during collaborative case-based ethics training we synthesised a scaffolding framework consisting of three levels: techniques, mechanisms and process. We organised 5 training sessions where 46 participants (including bachelor, master and PhD students as well as junior and senior academics) were involved. Data was collected as part of action research from group-work recordings and transcribed verbatim. Deductive qualitative analysis was implemented on transcripts based on the scaffolding framework. Our analysis revealed that structural scaffolding alone (learning material) is not always efficient with bachelor level students, they also require oral scaffolding when the need becomes apparent. Master's level students benefited most from wording the issues they needed to focus on. Doctoral students and senior academics needed scaffolding to maintain goal orientation. We end our article with some recommendations for facilitators of ethics education, and encourage using the scaffolding framework also in complex problem-solving beyond ethics training.