Background: Successful communication is vital to quality of life. One group commonly facing speech and communication difficulties is individuals with intellectual disability (ID). A novel route to encourage clear speech is offered by mainstream smart speakers (e.g., Amazon Alexa and Google Home). Smart speakers offer four factors important for learning: reward immediacy, spaced practice, autonomy/intrinsic motivation and reduced social barriers. Yet the potential of smart speakers to improve speech intelligibility has not been explored before. Aims: To determine whether providing individuals with intellectual disabilities with smart speaker devices improved ratings of speech intelligibility for: (1) phrases related to device use; and (2) unrelated words via a semi-randomized controlled trial. Methods & Procedures: In a semi-randomized controlled trial, an intervention group of adults with ID (N = 21) received smart speakers, while a control group (N = 22) did not. Before and after about 12 weeks, participants were recorded saying smart speaker-related phrases and unrelated words. Naïve participants then rated the intelligibility of the speech recordings. Outcomes & Results: The group that received smart speakers made significantly larger intelligibility gains than the control group. Although the effect size was modest, this difference was found for both smart speaker-related phrases and unrelated words. Conclusions & Implications: While the mechanism of action remains to be determined, the presence of smart speakers in the home had a demonstrable impact on ratings of speech intelligibility, and could provide cost-effective inclusive support for speech and communication improvement, improving the quality of life of vulnerable populations.