The present study investigates first language (L1) and second language (L2) associative stability (AS), operationalized as the repetition rate of response words over two sessions of the same word association test. Specifically, we compare the overall patterns of L1 and L2 AS, examine between-language AS correlations within individual learners, and explore the position effect of response words on AS. A total of 40 Chinese English learners completed two sessions of continuous word association tests over two weeks, in which they were required to produce three responses to each of the 30 cue words. The results revealed (1) a significantly higher repetition rate for L2 than for L1 word association responses; (2) a significant effect of response position on repetition rate, which declined from the first to the third position in both languages; and (3) a strong correlation between L1 and L2 response repetition for individual participants. These findings provide evidence for intra-individual consistency in L1 and L2 word association behavior and highlight the discrepancies between L1 and L2 lexical organization, which are probably due to weaknesses in the organization of the L2 semantic network. Implications for vocabulary teaching and future research are also discussed.