Ryazan (Russian: Рязань, IPA: [rʲɪˈzanʲ] (listen)) is the largest city and administrative center of Ryazan Oblast, Russia. The city is located on the banks of the Oka River in Central Russia, 196 km (122 mi) southeast of Moscow. As of the 2010 Census, Ryazan had a population of 524,927, making it the 33rd most populated city in Russia, and the fourth most populated in Central Russia after Moscow, Voronezh, and Yaroslavl.

Ryazan was previously known as Pereyaslavl-Ryazansky (Переяславль-Рязанский) until 1778, where it became the new capital of the Principality of Ryazan following the Mongol invasion of Kievan Rus'. The original capital, located 48 kilometres (30 mi) downstream on the Oka and now known as Old Ryazan (Старая Рязань, Staraya Ryazan), was among the first cities in Russia to be besieged and destroyed during the invasion that began in 1237.

The city is known for the Ryazan Kremlin, a historic museum; the Pozhalostin Museum, one of the oldest art museums in Russia; the Memorial Museum-Estate of Academician I.P. Pavlov; and the Ryazan Museum of Long-Range Aviation.

In 2022, the Ministry of Construction published an updated rating of the new urban digitalization index. Ryazan entered the top three cities with a population of 250 thousand to a million people