In this talk, I review the collider phenomenology associated with models of extra dimensions, namely, the model of flat compactified dimensions proposed by Arkani-Dimopoulos-Dvali, and the model of warped compactified dimensions by Randall and Sundrum. The novel feature of these models is that the fundamental scale is as low as TeV. The collider signatures are categorized into sub-Planckian and trans-Planckian. The sub-Planckian ones are due to graviton emission and exchanges, while the trans-Planckian includes black hole production and other stringy objects. There are also other variations in these models, e.g., gauge and Higgs fields in the extra dimensions can give rise to very different signatures. I will try to summarize the activities in the past few years, and highlight on the limits obtained from the existing collider data.