Nshima or nsima or Bidia is a cornmeal product and a staple food in Zambia, Malawi and the Kasai Oriental and Kasai Occidental provinces of the Democratic Republic of Congo. It is made from ground maize (corn) flour known locally as mealie-meal. Nshima is very similar to ugali or posho of East Africa, sadza of Zimbabwe, pap of South Africa and fufu of West Africa.

Maize was introduced to Africa from the Americas between 16th and 17th century. Prior to this, sorghum and millet were the principal cereals in most of Sub-Saharan Africa. Maize was readily accepted by African farmers as its cultivation was very similar to that of sorghum but with significantly higher yields. Eventually maize displaced sorghum as the primary cereal in all but the drier regions. Nshima is still made from sorghum flour though it is quite uncommon to encounter such. Cassava, which was also introduced from the Americas, can also be used to make nshima, either exclusively or mixed with maize flour, and is considered a delicacy by some.