The cellular signaling network plays a fundamental role during development and disease, especially cancer progression. By deregulating signaling pathways, cancer cells acquire hallmarks of the disease including uncontrolled proliferation, evasion from cell death, activation of angiogenesis, invasion, and metastasis. Noncoding RNAs make substantial contributions to regulating signal transduction in cancer, thereby promoting or suppressing different biological processes during tumorigenesis. This chapter provides an overview on the regulatory functions of noncoding RNAs in the signaling network in cancer cells. It summarizes examples of noncoding RNAs that act as oncogenes or tumor-suppressing genes involved in key signal pathways as well as signal crosstalk in cancer cells.