Background: The current literature suggests a link between dummy (or pacifier) use and a number of both positive and detrimental consequences. Positive consequences include soothing effect and protection from sudden infant death syndrome (SIDS), while negative ones include increased risk of otitis media and dental malformation. However, there is little research surrounding the impact of dummy use on the development of speech sounds. Aims: To investigate whether duration (in number of months) and frequency per day of dummy use have an individual or combined effect on the development of a child's speech, and if so, in what way. Methods & Procedures: A total of 100 British-English children aged 24-61 months and growing up in the UK were recruited through nurseries, playgroups and by word of mouth. Their parents were asked to complete a questionnaire about the duration and frequency of dummy use and factors known to influence the development of speech. Following this, the children's speech was assessed using the phonology section of the Diagnostic Evaluation of Articulation and Phonology (DEAP). Analysis of the DEAP was conducted to determine the percentage of consonants correct, number of age-appropriate, delayed and atypical errors. Dummy use and speech outcome measures were then analysed qualitatively and quantitatively using mean and median group comparisons alongside multivariate generalized least squares and generalized negative binomial modelling approaches to test for significant associations. Outcomes & Results: The results showed that the majority of speech outcomes are not significantly associated with dummy use, however measured, in bivariate or multivariate analyses. However, there is a significant association between increased atypical errors and greater frequency of daytime dummy use. This association is strengthened by restricted sampling within the younger members of the sample, with this association not observable within children older than 38 months, the median sample age. Conclusions & Implications: The evidence base for any effects of dummy use on speech is very small. Dummy use may increase the number of atypical speech errors a young child makes. However, only the frequency of daytime use seems relevant, not the duration or night-time use, and these errors may resolve over time.