Having a conversation with someone or even more within a group of people is complex. We are never taught at school how to do it, which implies we consider having a conversation as something simple and straightforward. Instead, we just learn from observing others. Some people are great conversationalists - it comes naturally to them - while others struggle. Some people may not fully understand how the process works, how turn-taking happens, don't understand visual cues such as body language and facial expressions, and fail to comprehend that some topics may be appropriate or inappropriate. This can be the case for both neurotypical and neurodivergent people. The Conversation skills Assessment Tool has been developed in this first instance to help in assessing and examining conversation skills in an intervention with young autistic adults on a virtual platform (a virtual world). This paper will present the evolution of the new measure through the exploratory phase, the development phase and finally a detailed account of the inter-rater reliability process. The intervention associated with this study was carried out though a multiple baseline design with 3 autistic participants (in their early 20 s) and took place over 4 phases (15-17 sessions). The sessions involved semi-structured conversations in face-to-face (phases 1 and 4) and virtual (phases 2 and 3) settings and were videotaped with the participants' consent. Twelve of those were used by this study in the development process through iterative inter-rater reliability stages between two coding teams. Evaluation of the Conversation skills Assessment Tool tool revealed the potential benefit of implementing interventions with measures that more objectively and concretely (e.g., by noting frequencies) assess observable behaviours that are associated with having positive conversations with others. Beyond this, it is anticipated that Conversation skills Assessment Tool can emerge as a tool capable of not only accounting for the environment an interaction takes place in (e.g., professional, casual), but also offers beneficial feedback for both autistic students and other populations (e.g., young children, English language learners). This measure has the potential to offer quantifiable and trackable guidance to people who have difficulties conversing. The authors do not wish to perpetuate an ableist social construct of what is a 'good' conversation, nor do they suggest that conversation skills training is useful solely for people with communication and/or socialization difficulties. Rather, they hope that Conversation skills Assessment Tool can be adopted more broadly to give both neurotypical and neurodivergent people a better understanding of how to communicate more effectively with others, while also becoming more aware and accepting of differing conversational styles. Because of its ability to track (or self-monitor) one's development of conversational skills over time, Conversation skills Assessment Tool could serve as an educative tool in early childhood education. It can be used by occupational/speech therapists and other professionals and also used to self-monitor one's development of conversational skills. Conversation skills Assessment Tool was developed to assess conversation skills on a one-to-one basis; therefore, another iteration of Conversation skills Assessment Tool would have to look at group conversations.