Epithelial-mesenchymal plasticity (EMP) defines the ability of cells to transdifferentiate between epithelial and mesenchymal states. Tumor cells undergoing EMP acquire invasive and migratory properties and the potential to disseminate to lymph nodes and distant sites. Based on this, EMP is increasingly highlighted as a factor, which determines tumor progression towards an invasive and metastatic state. EMP can be activated at different stages of cancer development and is regulated by a combination of genomic aberrations and the composition of the tumor microenvironment (TME). Activation of EMP in the primary tumor is induced by inflammatory signals that can be produced by both tumor and infiltrating immune cells in the microenvironment. EMP cells acquire properties of immune cells that are used for dissemination. Thus, EMP represents a link between tumor-related inflammation and cancer metastasis. Reciprocally, tumor cells that undergo EMP secrete factors that influence immune cell infiltration and activity in the TME. In line with this, it has been shown that EMP influences the efficacy of treatment with immunomodulatory therapies. Tumor cells with EMP properties are influenced by inflammatory signals and interact with immune cells along the metastatic journey. In this chapter, we describe EMP as a link between inflammation and cancer metastasis and specifically highlight recent findings showing the role of EMP in the primary TME, during lymph metastasis, in circulating tumor cells, and at distant metastasis.