Aitz Txiki is a peak of Biscay, Basque Country (Spain), 791 m. high.

Although it is the smallest one, it has the same rough and wild look, especially when viewed from the Atxarte pass that separates the mountain from the neighbouring Untxillaitz.

It has a double summit- the highest is Aitz Txiki and the lowest one is Artxua or Sorginkobetagana.

It is rough and difficult from all sides except the one faced to Atxarte, which is the main access route.

From there the proper ascent to Aitz Txiki begins without major difficulties through steep meadows.