Background: Interleukin-7 receptor (IL-7R) ${alpha}$-deficient mice have small numbers of B cells and ${alpha}{eta}$T cells in periphery, they totally lack ${gamma}{delta}$T cells. In addition, the V-J recombination and transcription of TCR ${gamma}$ genes is also severely impaired in IL-7R ${alpha}$-deficient mice. Stat5, a signaling molecule of the IL-7R, induces germline transcription in the TCR ${gamma}$ locus, and promotes V-J recombination and ${gamma}{delta}$T cell development. However, the roles for IL-7R signaling pathway in thymic or extrathymic ${gamma}{delta}$T cell development are largely unknown. Methods: To clarify the role of the IL-7 receptor in proliferation and survival of ${gamma}{delta}$T cells, we introduced the TCR ${gamma}{delta}$ transgene, $V_{{gamma}2}/V{delta}_5$, into IL-7R ${alpha}$-deficient mice, and investigated the development of ${gamma}{delta}$T cells. Results: We found that $V_{{gamma}2}/V{delta}_5$ transgene restored ${gamma}{delta}$T cells in the epithelium of the small intestine (IEL) but not in the thymus and the spleen. Further addition of a bcl-2 transgene resulted in partial recovery of ${gamma}{delta}$T cells in the thymus and the spleen of these mice. Conclusion: Taken together, this study revealed that the IL-7R ${alpha}$ is indispensable for proliferation and survival mainly in thymic ${gamma}{delta}$T cell development.