The regions of Niger are subdivided into 63 departments (French: départements). Before the devolution program on 1999–2005, these departments were styled arrondissements. Confusingly, the next level up (regions) had, before 2002-2005 been styled departments. Prior to a revision in 2011, there had been 36 departments. A draft law in August 2011 would expand that number to 63. Until 2010, arrondissements remained a proposed subdivision of departments, though none were used. The decentralisation process, begun in the 1995-1999 period replaced appointed Prefects at Departmental or Arrondissement level with elected councils, first elected in 1999. These were the first local elections held in the history of Niger. Officials elected at commune level are then selected as representatives at Departmental, regional, and National level councils and administration. The Ministry of Decentralisation was created to oversee this task, and to create a national consultative council of local officials.

On 1 August 2011, the National Assembly of Niger approved a draft law which would dramatically expand the number of departments to 63. The law will create 27 new departments centered on the former appointed sub departmental Postes Administratifs.

The 27 new department capitals will be: Aderbissanat, Iférouane, Ingall, Bosso, Goudoumaria, N'Gourti, Dioundiou, Falmèye, Tibiri, Bermo, Gazaoua, Bagaroua, Tassara, Tillia, Abala, Ayérou, Ballayara, Bankilaré, Banibangou, Gothèye, Torodi, Belbédji, Damagaram Takaya, Dungass, Takiéta, Tesker.

The 63 departments are broken down into communes. As of 2006 there were 265 communes, including communes urbaines (urban communes: centred in or as subdivisions of cities of over 10000), communes rurales (rural communes) centred in cities of under 10,000 and/or sparsely populated areas, and a variety of traditional (clan or tribal) bodies amongst semi-nomadic populations. The former postes administratifs (administrative posts) for largely uninhabited desert areas or military zones were incorporated as full departments with borders to be determined.

The 36 pre-2011 departments are listed below, by region.