A 36-year-old female with severe spastic dysarthria participated in this study. She received 4 weeks of individual, intensive voice-focused treatment. Voice recordings were conducted at three baseline points, immediately posttreatment, and at a 4-month follow-up. The primary outcome variables were selected acoustic measures of vocal function: sound pressure level (SPL), mean fundamental frequency (F0), maximum phonation time (MPT), jitter, shimmer, noise-to-harmonics ratio (NHR), and maximum phonation frequency range (MPFR). Significant pre-to-posttreatment changes (p < 0.05) were found for most acoustic variables. All acoustic gains, except for MPFR, were maintained at the 4-month follow-up. The significant posttreatment changes in the majority of the acoustic measures analyzed suggest that intensive voice-focused treatment may have the potential to improve vocal function in adults with severe spastic dysarthria secondary to cerebral palsy (CP). Evidence-based treatment options for voice disorders in adults with CP are limited. Results emphasize the need for more studies with this population.