Purpose The purpose of this study was to compare the effect of speech intervention provided with a low intensity with speech intervention provided with a high intensity on the speech and health-related quality of life (HRQoL) in Dutch-speaking children with a cleft palate with or without a cleft lip (CP ± L) between 4 and 12 years. Method A longitudinal, prospective, randomized controlled trial with a multiple baseline design was used. Twelve children with a CP ± L ( M age = 8.0 years, SD = 1.54) were divided into two groups using block randomization stratified by age and gender: One group received low-intensity speech intervention (LISI; n = 6) and one group received high-intensity speech intervention (HISI; n = 6). Children in the LISI group received intervention with a session duration of 1 hr, a dose frequency of 1 session per week, and a total intervention duration of 10 weeks. Children in the HISI group received intervention with a session duration of 1 hr, a dose frequency of 5 sessions per week, and a total intervention duration of 2 weeks. The cumulative intervention intensity was kept constant. Both groups received identical therapy programs provided by the same experienced speech therapist. Perceptual speech assessments were performed on baseline and posttreatment data points. Changes in HRQoL were assessed using the Velopharyngeal Insufficiency Effects on Life Outcomes (VELO) questionnaire. Both groups were compared over time using (generalized) linear mixed models. Results No significant Time × Group interactions were observed for the percentage of correctly produced consonants at the word and sentence levels, indicating no differences in evolution over time among the two groups. The variables speech understandability, speech acceptability, and the total VELO scores significantly improved following HISI, but not following LISI. Conclusions Children in the HISI group made equal and, for some variables, even superior progress in only 2 weeks of therapy compared to children in the LISI group who received 10 weeks of therapy. HISI is a promising strategy to improve speech outcomes and HRQoL in a shorter time period.