Designing assessment that is effective and equitable is challenging enough when students and teachers come from the same educational system and share the same first language. It is even harder in EMI contexts. Until very recently, assessment was a marginal issue in EMI research, but the Journal of English-Medium Instruction shone the spotlight on assessment in a special issue in 2022, recognising that more attention on assessment practices and on increasing EMI teachers’ assessment literacy is needed (Dimova & Kling. Journal of English-Medium Instruction, 1(2), 137–152, 2022). This chapter addresses the issue of professional development for assessment in EMI, with a focus on Italian higher education. In Italy, very little research on EMI assessment has been carried out and there is little professional development that focuses specifically on assessment. The purpose of this chapter is thus to provide insights from evidence-based training and reflect on a PD workshop for EMI assessment in the Italian context, taking into account a worldwide shift towards a formative, assessment-for-learning paradigm (Inbar-Lourie. Journal of English-Medium Instruction, 1(2), 204–231, 2022), increasing diversity in the classroom, and the local culture of teaching, learning and assessment. The training also addresses the interaction of language and content in EMI settings. For EMI professional development to be effective it needs to engage teachers in a cycle of reflect-review-act-review over time, addressing the interaction between language and content in EMI classrooms and assessment practices, and increasing teachers’ assessment and feedback literacy.