Acquiescence is the consistent tendency toward a shift of responses in the direction of agreement rather than disagreement regardless of the content, and it is usually measured by manifest approach based on a deviation from the median of the response scale and by latent approach using confirmatory factor analysis. Our goal was to investigate whether acquiescence, as measured by both approaches, was stable over time. We explored the relationship of acquiescence with variables that are usually considered to be validating criteria for acquiescence. The research was conducted on a general sample of 443 Slovak adult participants, while using the BFI-2 as the tool to identify acquiescence. Data were collected twice with an interval of almost two years. The results showed that both approaches showed relative stability over time, with correlation coefficients r = .50 for the manifest and r = .55 for the latent approach. The time stability of acquiescence suggests that acquiescence is more of a participant-related than a situation-related construct. Both approaches positively correlated with counts of agreements used as validating variables. For future research, we recommend using CFA to identify acquiescence because of the low reliability of the manifest approach and counts of agreements from another time point as a validity criterion whenever possible.