This study examined variability in Chinese as a Foreign Language (CFL) learners' development of the Chinese numeral classifier system from a dynamic systems approach. Our data consisted of a longitudinal corpus of 657 essays written by CFL learners at lower and higher intermediate levels and a corpus of 100 essays written by native speakers (NSs) of Chinese. A combination of quantitative and qualitative methods was employed to analyze the fluency, diversity, and accuracy of learners' and NSs' classifier use. Usage by 4 focal learners from the higher immediate level was then closely examined to discover inter- and intra-individual variability in learners' development of these dimensions and to reveal the patterns of interaction among these dimensions. Learners exhibited varied, nonlinear developmental paths for all three dimensions, with different degrees of fluctuation and regression for each path. The three dimensions did not always develop in parallel, but interacted with each other in divergent ways. Pedagogically, we advocate for a collocational approach to presenting and teaching classifiers and recommend that tailored assistance be provided to individual learners. (Contains 7 tables, 3 figures, and 3 notes.)