**Paper:** Anonymized authors (in prep). Nameability supports rule-based category learning in children and adults. **Abstract:** Learning abstract, rule-based categories is crucial to children’s development, from learning how to maneuver through the world (e.g., knowing to stop at a red light) to abstract reasoning (e.g., learning that a three-sided shape is a triangle). How do children learn rule-based categories? Past work with adults suggests that verbal labels may support novel category induction by providing compact hypotheses about category-relevant features. We asked whether children also make use of accessible labels to guide category learning. We tested children’s (N = 97; 4 - 6 years of age) and adults’ (N = 90) ability to learn a novel category in which the colors that perfectly predicted category membership were either easy to name (e.g., “red” and “brown”) or more difficult to name (e.g., “mauve” and “chartreuse”). Both children and adults showed better learning when the categories were composed of more nameable color features compared to less nameable color features, though the effect of nameability on category learning was stronger for adults than children. Children’s success in learning categories with difficult-to-name features was related to knowledge of difficult-to-name colors. Together, these results provide evidence that rule-based category learning may be supported by the emerging ability to form verbal hypotheses about category membership (e.g., “the red ones belong to category A”). **Repository materials:** - **analysis_scripts:** Folder containing analysis scripts (including an R markdown file with the core analyses) as well as key outputs (figures, model outputs) - **data:** Folder containing processed experimental data and codebook - **experiment_scripts:** Experimental scripts used to present the experiment (python-/ psychopy-based) - **norming_results:** Data and analysis scripts for the perceptual discriminability norming task **Analysis Walkthrough:** https://rpubs.com/zcm/color-rule-kid **Norming Results Walkthrough:** https://rpubs.com/zcm/color-rule-kid-norming