<p>Many studies have explored the relationship between music and developmental skills, suggesting that musical training may foster rhythm, lexicon, and executive functions. However, the existing literature has mainly focused on preschoolers, considering a single developmental domain or long-term programmes. This study implemented an 8-week music training for 2- and 4-year-olds with a sample including 54 toddlers (<i>M</i>_age = 29.0 months) and 54 preschoolers (<i>M</i>_age = 52.9 months), divided into experimental (62) and control (46) groups. A pre-post training design was employed, considering rhythm (using the Rhythmic Imitation test, Stamback, <CitationRef CitationID="CR69">1980</CitationRef>), lexicon (using the Picture Naming Game, Bello et al., <CitationRef CitationID="CR3">2010</CitationRef> and the Peabody Picture Vocabulary Test, Stella et al., <CitationRef CitationID="CR70">2000</CitationRef>), and executive functions (using Circle Drawing, Fish, Stroop Day/Night, Keep Track, Usai et al. <CitationRef CitationID="CR77">2017a</CitationRef>). Repeated-measures ANCOVAs with parental education as covariate showed a significant training effect on rhythmic skills both for toddlers and preschoolers, with the latter showing a greater increase in rhythmic skill than the former. An effect was also found on executive functions in preschoolers, but not on lexicon at the two ages. Finally, a correlational analysis showed a partial relation between rhythm and lexical comprehension, inhibitory control speed, and working memory accuracy in the older sample. Music training emerges as a sensitive approach to support early skills of 2 and 4-year-olds in nursery and kindergarten, promoting continuity and integration in educational programming.</p>