Seyni Oumarou (an haife shi a 9 ga watan Agusta shekara ta 1951) ɗan siyasan Nijar ne wanda ya kasance Firayim Minista na Nijar daga watan Yunin shekara ta 2007 zuwa Satumba na shekara ta 2009 da kuma Shugaban Majalisar Dokokin Nijar daga watan Nuwamba shekara ta 2009 zuwa watan Fabrairu shekara ta 2010. Ya fito ne daga yammacin ƙasar kuma ɗan kabilar Djerma (Ba Zabarme) ne. Tun watan Nuwamba na shekara ta 2008, ya kasance shugaban ƙungiyar National Movement for the Development of Society (MNSD). Bai yi nasarar tsayawa takarar shugaban kasa ba a shekara ta 2011 da 2016 ba. Bayan shekaru a matsayin jagoran adawa a karkashin Shugaba Mahamadou Issoufou, an nada shi mukamin Babban Wakilin Shugaban kasa a watan Oktoban shekara ta 2016. Seyni Oumarou an haife shi a Tillabéri . Sunan danginsa, Seyni, yawanci yakan sa sunansa, kuma wani lokacin ana rubuta shi Seini ko Seïni . Ya kasance Darakta-Janar na Kamfanin Canja Takarda na Nijar (ENITRAP) daga shekarar 1987 zuwa shekarar 1998, sannan a shekarar 1995 ya zama Mashawarci na Musamman ga Firayim Minista Hama Amadou .