This meta-analytic review explored the characteristics and effectiveness of combined language (e.g., vocabulary) and code (e.g., phonological awareness) interventions, including synergistic intervention effects for at-risk preschoolers. Data from 29 randomized controlled trials, published before March 2023, reporting on 43 interventions, including 9333 children (4-6 years; 55% male, 45% African American, 30% Hispanic) were included in the meta-analyses. Composite intervention effects were small: language (g = 0.11) and code (g = 0.23). Language and code outcomes were significantly related (p = 0.032). Interventions equally targeting code and language subskills produced equivalent or greater code and language outcomes than those with an unequal emphasis. Implications for future combined intervention studies are discussed.