Electro-optic frequency combs (EOFCs), produced by electro-optic modulation, are optical frequency combs with tunable spacing, high comb-tooth power, and strong coherence. They bridge microwave and optical domains and find applications in spectroscopy, precision ranging, and optical communications. Conventional EOFCs depend on bulky, power-intensive devices, which hinder practical use. Advances in thin-film lithium niobate (TFLN) and silicon nitride (SiN) have driven the rise of chip-scale integrated EOFCs as a major research focus. Recent progress using Mach–Zehnder modulators, phase modulators, and microring resonators has improved spectral flatness, modulation efficiency, and bandwidth coverage. This paper reviews EOFC generation mechanisms and representative designs, compares implementations on different material platforms, and highlights prospects in spectroscopy, ranging, and communications. Finally, current challenges and future research directions are outlined.