Kozmodemyansk (Russian: Козьмодемьянск) is the name of several inhabited localities in Russia.

Urban localities

• Kozmodemyansk, Mari El Republic, a town in the Mari El Republic; 56°20′N 46°34′E / 56.333°N 46.567°E / 56.333; 46.567

Rural localities

• Kozmodemyansk, Sovetsky District, Mari El Republic, a village in Mikhaylovsky Rural Okrug of Sovetsky District in the Mari El Republic; 56°39′N 48°19′E / 56.650°N 48.317°E / 56.650; 48.317
• Kozmodemyansk, Perm Krai, a selo in Karagaysky District of Perm Krai
• Kozmodemyansk (selo), Yaroslavl Oblast, a selo in Melenkovsky Rural Okrug of Yaroslavsky District in Yaroslavl Oblast
• Kozmodemyansk (settlement), Yaroslavl Oblast, a settlement in Melenkovsky Rural Okrug of Yaroslavsky District in Yaroslavl Oblast