Staufen1 (STAU1) and Lin28B are RNA-binding proteins that are involved in neuronal differentiation as a function of post-transcriptional regulation. STAU1 triggers post-transcriptional regulation, including mRNA export, mRNA relocation, translation and mRNA decay. Lin28B also has multiple functions in miRNA biogenesis and the regulation of translation. Here, we examined the connection between STAU1 and Lin28B and found that Lin28B regulates the abundance of STAU1 mRNA via miRNA maturation. Decreases in the expression of both STAU1 and Lin28B were observed during neuronal differentiation. Depletion of STAU1 or Lin28B inhibited neuronal differentiation, and overexpression of STAU1 or Lin28B enhanced neuronal differentiation. Interestingly, the stability of STAU1 mRNA was modulated by miR-142-3p, whose maturation was regulated by Lin28B. Thus, miR-142-3p expression increased as Lin28B expression decreased during differentiation, leading to the reduction of STAU1 expression. The transcriptome from Staufen-mediated mRNA decay (SMD) targets during differentiation was analyzed, confirming that STAU1 was a key factor in neuronal differentiation. In support of this finding, regulation of STAU1 expression in mouse neural precursor cells had the same effects on neuronal differentiation as it did in human neuroblastoma cells. These results revealed the collaboration of two RNA-binding proteins, STAU1 and Lin28B, as a regulatory mechanism in neuronal differentiation.