Individual differences in language processing are prevalent in our daily lives. However, for decades, psycholinguistic research has largely ignored variation in the normal range of abilities. Recently, scientists have begun to acknowledge the importance of inter-individual variability for a comprehensive characterization of the language system. In spite of this change of attitude, empirical research on individual differences is still sparse, which is in part due to the lack of a suitable research tool. Here, we present a novel battery of behavioral tests for assessing individual differences in language skills in younger adults. The Dutch prototype comprises 29 subtests and assesses many aspects of language knowledge (grammar and vocabulary), linguistic processing skills (word and sentence level) and general cognitive abilities involved in using language (e.g., WM, IQ). Using the battery, researchers can determine performance profiles for individuals and link them to neurobiological or genetic data.