Between 6 and 9 years of age, children's free associations shift from syntagmatic to paradigmatic relationships. "Syntagmatic relations" are words that are syntactically adjacent, thematically related ("summer-vacation"), or both; "paradigmatic relations" are words from the same grammatical class, taxonomic category ("summer-winter"), or both. Infant researchers have reliably found evidence for the activation of paradigmatic relationships by 24 months. Because of a lack of data from children aged 3 to 5 years, the developmental trajectory of paradigmatic relations is unclear. With age-appropriate stimuli, this work is among the first to collect free association data for children under 5. Children (n = 60; age range = 3-8 years) and adults (n = 60; age range = 18 to 43 years) were instructed to respond to a prime word with the first word that came to mind. Unifying the data from previous studies with infants and older children, our data suggest that paradigmatic relations are present in early childhood but also increase in prevalence with age. Several exploratory analyses revealed that younger children gave more varied responses, suggesting that early lexical-semantic networks are more idiosyncratic. We also found preliminary evidence that responses varied by grammatical class and gender across age groups, with implications for both theory and experimental design. By continuing data collection across the life span and making the dataset public, future work will further elucidate the development of lexical-semantic networks from early childhood onward.