Recent work has shown that individuals vary in phonetic behaviors in ways that deviate from group norms and are not attributable to sociolinguistically relevant dimensions such as gender or social class. However, it is unknown whether these individual differences observed in the lab are stable characteristics of individuals or whether they simply reflect noise or sporadic fluctuations. This study investigates the individual-level stability in imitation of a model talker's artificially-lengthened VOT. We use a test-retest design in which the same set of participants perform the same lexical shadowing task on two separate occasions and find that degree of convergence or divergence is highly correlated on an individual basis across visits. Further, we find a strong correlation between individual VOT shifts toward a male model talker and shifts toward a female model talker. Findings contribute to a growing body of literature suggesting that averaging over groups of participants masks the complexity of phonetic behaviors, such as imitation, and suggest that individual differences in phonetic behavior are an area of promising future study.