Diverse learners bring a broad range of experiences and perspectives into the classroom and offer a powerful resource for learning. However, they also pose major challenge to practitioners and researchers working in the field of education. Biases and inequitable social consequences may occur when assessing young children, students with disabilities, high-ability students, and culturally and linguistically diverse learners. Through a compilation of empirical studies, this book aims to present both theory and applications of assessment in educational research. Each chapter focuses on different groups of learners, which include Malaysian students, Japanese pre-schoolers, gifted Saudi students, Nigerian adolescents, and foreign language learners in Gaza. Based on the assessment procedures and outcomes obtained in each study, good practices of assessment are provided at the end of the book.