Purpose: The purpose of this longitudinal study was to examine the effect of time and sentence length on speech rate and its characteristics, articulation rate and pauses, within 2 groups of children with cerebral palsy (CP). Method: Thirty-four children with CP, 18 with no speech motor involvement and 16 with speech motor involvement, produced sentences of varying lengths at 3 time points that were 1 year apart (mean age = 56 months at first time point). Dependent measures included speech rate, articulation rate, proportion of time spent pausing, and average number and duration of pauses. Results: There were no significant effects of time. For children with no speech motor involvement, speech rate increased with longer sentences due to increased articulation rate. For children with speech motor involvement, speech rate did not change with sentence length due to significant increases in the proportion of time spent pausing and average number of pauses in longer sentences. Conclusions: There were no significant age-related differences in speech rate in children with CP regardless of group membership. Sentence length differentially impacted speech rate and its characteristics in both groups of children with CP. This may be due to cognitive-linguistic and/or speech motor control factors.