Fyodor I Ivanovich (Russian: Фёдор I Иванович or Feodor I Ioannovich Russian: Феодор I Иоаннович; 31 May 1557 – 16/17 January (NS) 1598) was the last Rurikid Tsar of Russia (1584 – 1598), son of Ivan the Terrible and Anastasia Romanovna. In English he is sometimes called Feodor the Bellringer in consequence of his strong faith and inclination to travel the land and ring the bells at churches. However, in Russian the name "Bellringer" is hardly ever used. In Russian documents he is sometimes called blessed (Russian: Блаженный). He was born in Moscow and crowned Tsar and Autocrat of all Russia at Assumption Cathedral, Moscow, on 31 May 1584.

Feodor was a simple minded man who took little interest in politics, and was never considered a candidate for the Russian throne until the death of his elder brother Ivan Ivanovich. He was of pious character and spent most of his time in prayers. Having inherited a land devastated by the excesses of his father, Ivan the Terrible, he left the task of governing the country to his able brother-in-law, Boris Godunov. Feodor I's weakness and inability to rule effectively have been sometimes attributed to mental retardation.

Unlike his father, Feodor had no enthusiasm in maintaining exclusive trading rights with the Kingdom of England. Feodor declared his kingdom open to all foreigners, and dismissed the English ambassador Sir Jerome Bowes, whose pomposity had been tolerated by Feodor's father. Elizabeth I sent a new ambassador, Giles Fletcher, the Elder, to demand Boris Godunov to convince the tsar to reconsider. The negotiations failed, due to Fletcher addressing Feodor with two of his titles omitted. Elizabeth continued to appeal to Feodor in half appealing, half reproachful letters. She proposed an alliance, something which she had refused to do when offered one by Feodor's father, but was turned down.

He married in 1580 Irina (Alexandra) Feodorovna Godunova (1557 – 26 October / 23 November 1603), sister of Boris Godunov. In 1588 he added on to Saint Basil's Cathedral in the Red Square, originally constructed between 1555 - 1561 by his father Ivan IV (or Ivan the Terrible). Feodor built more towers on the eastern side of the cathedral over the grave of St. Basil the blessed.

After almost twelve years of marriage, Tsaritsa Irina gave birth to a daughter, Feodosia, in 1592. Feodosia died in 1594 aged two. Feodor's failure to sire other children brought an end to the centuries old central branch of the Rurik dynasty (although many princes of later times are descendants of Rurik as well). Termination of the dynasty can also be considered to be one of the reasons of the Time of Troubles. He died in Moscow and was buried at Archangel Cathedral, Kremlin.

His troubled reign was dramatised by Aleksey Konstantinovich Tolstoy in his verse drama Tsar Fiodor Ioannovich (1868).