Needle ice is a needle-shaped column of ice formed by groundwater. Needle ice forms when the temperature of the soil is above 0 °C (32 °F) and the surface temperature of the air is below 0 °C (32 °F). Liquid water underground rises to the surface by capillary action, and then freezes and contributes to a growing needle-like ice column. The process usually occurs at night when the air temperature reaches its minimum.

The ice needles are typically a few centimetres long. While growing, they may lift or push away small soil particles. On sloped surfaces, needle ice may be a factor contributing to soil creep.

Alternate names for needle ice are "frost pillars" ("Säuleneis" in German), "frost column", "Spew Ice", "Kammeis" (a German term meaning "comb ice"), "Stängeleis" (another German term referring to the stem-like structures), "shimobashira" (霜柱, a Japanese term meaning frost pillars), or "pipkrake" (from Swedish pipa (tube) and krake (weak, fine), coined in 1907 by Henrik Hesselman).

The similar phenomena of frost flowers and hair ice can occur on living or dead plants, especially on wood.