Different processes shaping land-use patterns are observed at different scales. In land-use modelling, scale can influence the measurement and quantitative description of land-use patterns and can therefore significantly impact the behaviour of model parameters that describe land-use change processes. We present results of a rigorous sensitivity analysis of a cellular urban land-use-change model, SLEUTH, testing its performance in response to varying cell resolutions. Specifically, we examine the behaviour of each type of urban growth rule across different cell sizes, and explore the model's ability to capture growth rates and patterns across scales. Our findings suggest that SLEUTH's sensitivity to scale extend beyond issues of calibration. While the model was able to capture the rate of growth reliably across all cell sizes, differences in its ability to simulate growth patterns across scales were substantial. We also observed significant differences in the sensitivity of the growth rules across cell sizes, indicating that SLEUTH may perform better at certain cell sizes than at others. These findings emphasize the importance of scale considerations in land-use-change modelling research, particularly in terms of determining the relevant and appropriate scales of enquiry for the processes being simulated.