Translationally controlled tumour protein (TCTP) is a highly conserved protein in eukaryotes and has been implicated in multiple events, including growth control. To find new roles of TCTP in vivo, we performed biochemical and genetic screens for TCTP-interacting genes. From this screen, we identified Coracle (Cora) as a new binding partner of TCTP. Cora is a septate junction protein of the protein 4.1 family required for maintaining the transepithelial barrier and the apical basal epithelial polarity together with Yurt, Neurexin Ⅳ and Na+/K+ ATPase. We show that cora mutations enhance the phenotypes of TCTP knockdown by RNAi expression, resulting in synthetic lethality or headless flies depending on the affected tissues. Biochemical analyses indicate that Cora forms a complex with TCTP by direct binding. Loss of Cora causes decreased levels of TCTP protein and affects Arm expression. Loss of TCTP also shows reduction of Cora and Arm expression. Further, TCTP and Cora show overlapping localization in epithelial tissues. We also identified additional biochemical and genetic interaction of TCTP with other septate junction genes. Taken together, this study suggests a novel linkage between TCTP and the septate junction proteins implicated in growth regulation.