MiR-205 plays an important role during adipogenesis by modulating the Wnt signaling pathway. Here, we report that miR-205 can regulate the differentiation of 3T3-L1 preadipocyte cells by targeting glycogen synthase kinase 3 beta (GSK-3 beta), which is a negative regulatory factor of Wnt signaling. When transiently overexpressed in 3T3-L1 cells, miR-205 suppressed the translation of GSK-3 beta, resulting in increased expression of beta-catenin, which can promote cell proliferation by facilitating the transcription of the Wnt target genes cyclin D1 and c-Myc. However, stable overexpression of miR-205 in 3T3-L1 cells did not show any apparent inhibitory effect on adipogenic differentiation. While endogenous miR-205 was inhibited in 3T3-L1 cells, the adipogenesis marker gene, C/EBP alpha, was significantly activated and more lipid droplets appeared in differentiated adipocytes. However, systemic silencing of miR-205 in mice by using a locked-nucleic-acid-modified oligonucleotide (LNA-antimiR) did not lead to any observable increase in adipose tissue differentiation, implying that, as opposed to the findings from 3T3-L1 cells, miR-205 is dispensable for adipose tissue development in mice.