Research has suggested an interference effect for words taught in semantic clusters due to the semantic links connecting the words. Thematic clustering of vocabulary is an alternative method of presenting new words to second language (L2) learners. However, what is known about the effects of semantic and thematic clustering has been uncovered through the recruitment of adult learners, with little research conducted with very young learners. Moreover, language textbooks and curriculums for very young learners continue to structure vocabulary semantically. Embedded instruction using storybook contexts has been suggested as a suitable context-based vocabulary teaching technique although knowledge of its effects is limited. To investigate this claim, a quasi-experimental within-subjects design was used to investigate whether embedded instruction could differentially affect very young L2 learners' learning of new vocabulary taught in either semantic or thematic clusters (N = 38) compared to a control (N = 15). The findings suggest that embedded instruction is beneficial for very young L2 learners' vocabulary learning regardless of the clustering type. Participants gained and retained over time considerable receptive and productive vocabulary knowledge for both semantic and thematic clustered words, indicating that embedding vocabulary in storybook contexts may reduce the potential for interference between target words in semantic clusters.