Patriarch Mstyslav, secular name Stepan Ivanovych Skrypnyk (10 April 1898 – 11 June 1993), was a Ukrainian Orthodox Church hierarch.

In this period Skrypnyk collaborated with the Polish voivode of Volhynia, Henryk Józewski in his Prometheist policies supporting moderate Ukrainians as a counterweight to Soviet communism.

At the beginning of the Second World War, the Ukrainian life in some Nazi-occupied territories of Poland initially experienced a significant degree of revival[3] as the Nazi policies played with pitting the ethnic groups with a historically complicated relationship against each other, giving an upper hand to Poles or Ukrainians in different regions as the Nazis saw fit.

He took monastic vows in the following month and soon after was ordained (May 14) as the Bishop Mstyslav of Pereiaslav by the Ukrainian Autocephalous Orthodox Church (UAOC).

In the US, Bishop Mstyslav began extensive church activity with the Ukrainian Orthodox Center, a publishing house, library and seminary being built in South Bound Brook, New Jersey.

After the death of Metropolitan Nikanor (Abramovych) in 1969, his authority was extended over the Ukrainian Autocephalous Orthodox Churches of Europe and Australia.

During his meetings with the then Ecumenical Patriarch, Athenagoras I both separately in 1963 and 1971, he brought up the issue of the canonical recognition of the Ukrainian Diaspora churches (UAOC was banned in the USSR, and hence in Soviet Ukraine at that time).

In June 1992, a unification Sobor was held which united the UAOC with one part of the Ukrainian Orthodox Church (Moscow Patriarchate), then led by Metropolitan Filaret (Denysenko).