Extracellular vesicle and particle microRNAs (EVP miRNA) in milk have the capacity to facilitate maternal-infant communication in the postpartum period and are hypothesized to play important roles in child development. Maternal diet quality has been linked to milk macronutrient composition, microbiota profiles, as well as various child health outcomes. The aim of this study was to assess the association between maternal diet quality and milk EVP miRNA. In a pilot study of 54 participants from a larger birth cohort study, diet quality was measure by the Alternative Healthy Eating Index 2010 (AHEI-2010) during the second trimester of pregnancy and 798 EVP miRNA were profiled in mature milk samples (collected approximately six weeks postpartum) using the NanoString nCounter platform. In covariate-adjusted models, AHEI-2010 was positively associated ( < 0.05) with levels of miR-1283, miR-520h, and mir-570-3p in milk EVPs. Predicted target genes of these diet-associated miRNA are enriched in pathways related to lactation and mammary development (PI3 kinase signaling and Wnt signaling pathways) and milk protein and fat synthesis (PI3 kinase signaling). Further research is needed to investigate whether these diet-associated miRNA influence lactation, human milk quality, and child growth and development.