An adze ( /ˈædz/; American English: adz) is a tool used for smoothing or carving rough-cut wood in hand woodworking. Generally, the user stands astride a board or log and swings the adze downwards towards his feet, chipping off pieces of wood, moving backwards as they go and leaving a relatively smooth surface behind. Adzes are most often used for squaring up logs, or for hollowing out timber.

The adze is also used for demolition of old buildings by hand for salvage. The single tool can serve all the needs of deconstruction with proper use.

The blade of an adze is set at right angles to the tool's shaft (like a hoe or plane), unlike the blade of an axe which is set in line with the shaft. A very similar (but blunt) tool used for digging in hard ground is called a mattock.

In central Europe, adzes made by knapping flint are known from the late Mesolithic onwards ("Scheibenbeile"). Polished adzes and axes made of ground stone, such as amphibolite, basalt or Jadeite are typical for the Neolithic period. Shoe-last adzes or celts, named for their typical shape, are found in the Linear Pottery and Rössen cultures of the early Neolithic. Adzes were also made and used by prehistoric southeast Asian cultures, especially in the Mekong River basin.^{[citation needed]}