Ice and liquid water have been key agents in shaping the Martian surface, operating through both surface and subsurface processes. Polar layered ice caps preserve a detailed record of climate evolution, with seasonal CO₂ exchange influencing atmospheric pressure cycles. Across the mid-latitudes, ice-related landforms such as mantling deposits and glacier-like features indicate widespread past glaciation driven by orbital variations. Recent discoveries, including excavated subsurface ice and equatorial glacial remnants, reveal that ice was once more extensive and dynamic. Water-carved geomorphology, such as valley networks and outflow channels, provide strong evidence for sustained and catastrophic liquid water activity in early Mars history. Decades of remote sensing discoveries of former crater lakes, deltas, and possible oceanic deposits further support the existence of standing water and complex hydrological systems. Together, these features point to a planet shaped by interacting ice and water processes under shifting climatic conditions, including episodic warming and melting events.