Alexey (Aleksey) (Russian: Алексе́й, ) is a Russian male first name deriving from the Greek Alexios (Αλέξιος), meaning "Defender", and thus of the same origin as the Latin Alexius.

Alexey may also be romanized as "Alexei", "Aleksei", "Aleksey", "Alexej", "Aleksej", etc. It has been commonly westernized as Alexis.

Names of many persons of Ukrainian and Belarusian origin previously known as Alexey are now often romanized as Olexiy (Олексiй) and Alyaxey (Аляксей), respectively.

The Russian Orthodox Church uses the Old Church Slavonic version, Alexiy (Алексiй, or Алексий in modern spelling), for its Saints and hierarchs (most notably, this is the form used for Patriarchs Alexius I and Alexius II).

The common hypocoristic is Alyosha (Алёша) or simply Lyosha (Лёша). These may be further transformed into Alyoshka, Alyoshenka, Lyoshka, Lyoha, Lyoshenka (Алёша, Алёшка, Алёшенька, Лёша, Лёшка, Лёха, Лёшенька), sometimes rendered as Alesha/Aleshenka in English. The form Alyosha may be used as a full first name in Bulgaria (Альоша) and Armenia.

In theory, Alexia is the female form. It is however virtually non-existent in Russian-speaking countries. A popular Ukrainian and Belarusian female name Olesia/Alesia is one possible form.

The patronymics based on Alexey are Alexeyevich (male) and Alexeyevna (female).

The following surnames derive from Alexey and its various forms:

  • Alexeyev
  • Alexeyevsky
  • Alyoshin
  • Alyokhin (see also Alekhine)
  • Lyoshin
  • Alexeytsev
  • Alexeychuk
  • Alexeychik
  • Alexeyuk
  • Alexeyenko
  • Alexeychenko
  • Alexievich

Alexeyevka is a common Russian village name.

Read more about Alexey:  Persons Known By First Name Alexey