21st century skills are generally regarded as the skills that individuals need to have in today's world, and they are categorized in various ways by different institutions and organizations. In addition to activities and applications aimed at acquiring these skills in educational environments, assessment processes have also been the subject of numerous studies. There are various 21st century skill scales available in the literature, targeting various groups. Some of these scales are developed to measure broader skill sets. In this regard, we see a broader classification of skills in the “Inclusive 21st Century Skills Model”. This up-to-date model developed considering our education system consists of 7 main skills, 46 sub-skills, and 11 values. This study provides recommendations for the assessment of skills to be acquired through the use of the model in science education. In line with the purpose of this study, the definition of 21st century skills and the frameworks found in the literature will first be addressed. Then, the Inclusive 21st Century Skills Model developed for the classification of these skills will be introduced, and finally, suggestions will be presented on how this model can be integrated into assessment and evaluation processes specifically in science education.