Epithelial apicobasal polarity has fundamental roles in epithelial physiology and morphogenesis. The PAR complex, comprising PAR-3, PAR-6 and aPKC, is involved in determining cell polarity in various biological contexts, including in epithelial cells. However, it is not fully understood how the PAR complex induces apicobasal polarity. In this study, we show that PAR-3 regulates the protein expression of Girdin (GIV/CCDC88A), a guanine nucleotide exchange factor (GEF) for heterotrimeric Gαi subunits, at the transcriptional level by cooperating with the AP-2 transcription factor. In addition, we confirmed that PAR-3 physically interacts with Girdin, and show that Girdin, together with the Gαi3, controls tight junction formation, apical domain development and actin organization downstream of PAR-3. Taken together, our findings suggest that transcriptional upregulation of Girdin and Girdin–Gαi3 signaling play crucial roles in regulating epithelial apicobasal polarity via the PAR complex.