Although emerging data support crucial roles for microRNAs (miRNAs) during adipogenesis, the detailed mechanisms remain largely unknown. In this study, it was shown that in rabbits, levels of miR-148a-3p not only increased in white adipose tissue during early stages of growth but also during in vitro cultured preadipocyte differentiation. Furthermore, overexpression of miR-148a-3p significantly upregulated the mRNA levels of PPARγ, C/EBPα, and FABP4, as well as the protein levels of PPARγ, as indicated by qPCR and western blotting analyses. Overexpression of miR-148a-3p also promoted intracellular triglyceride accumulation. In contrast, downregulation of miR-148a-3p inhibited the differentiation of rabbit preadipocytes. Next, based on target gene prediction and a luciferase reporter assay, we further demonstrated that miR-148a-3p directly targeted one of the 3' untranslated regions of PTEN. Finally, it was observed inhibition of PTEN by siRNA promoted rabbit preadipocyte differentiation. Taken together, our results suggested that miR-148a-3p could be involved in regulating rabbit preadipocyte differentiation through inhibiting expression of PTEN, which further highlighted the importance of miRNAs during adipogenesis.