What alphabet is used to write modern Russian?

The alphabet used to write modern Russian is the Cyrillic alphabet.

Modern Russian uses a national form of Cyrillic containing 33 letters: 20 consonant letters, 10 vowel letters, the semivowel or consonant й, and the signs ъ and ь. Those two signs do not represent ordinary vowel or consonant sounds; instead, they affect pronunciation and the softness or separation of neighboring sounds.

Cyrillic was developed in the 9th century for writing Old Church Slavonic, the first major literary language of the Slavs. It was later adapted for Old East Slavic in Kievan Rus’, and the tradition eventually produced the Russian alphabet. A major Russian spelling reform in 1917–1918 removed several obsolete letters and created the modern 33-letter system.

A frequent mistake is treating “Cyrillic” as a single identical alphabet. Different languages use different Cyrillic alphabets: Bulgarian, Serbian, Ukrainian and Russian have distinct letters and spelling rules. Russian also generally omits written stress marks, except in dictionaries, textbooks and cases where pronunciation needs clarification.