Northwestern Mari (Маре йӹлмӹ) is a Uralic language variety closely related to Hill Mari and Meadow Mari. With the first of them Northwestern Mari joins as a dialect group of Western Mari language. Northwestern Mari is the language of Northwestern Mari people, who live in Russia in the Yaransky, Tuzhinsky, Kiknursky, Sanchursky districts of Kirov Oblast, Tonshayevsky, Sharangsky and Tonkinsky districts of Nizhny Novgorod Oblast and partly in Kilemarsky and Medvedevsky districts of Mari El. It is written using the Northwestern Mari Cyrillic script, but does not have an official status in any subjects of the Russian Federation.

Northwestern Mari people have difficulties understanding both other literary languages. The first book in Northwestern Mari, Маре букварь (Mare bukvar, Northwestern Mari primer) was printed in 1995, and the dialect thereby became the third literary standard.