Alexander Andreevich Alexandrov (born Nadezhda Andreyevna Durova; 17 September 1783 – 21 March 1866) was a Russian cavalry soldier and writer who participated in the Napoleonic Wars. Alexandrov was assigned female at birth, but solely presented as a man in adulthood.

At twenty-three, Alexandrov fled his home, and enlisted in an uhlan (light cavalry) regiment, dressing as a male soldier and taking on the name Alexander Sokolov. He served from 1806 to 1816, and received the Cross of St. George for bravery. After his service, he published a memoir, originally titled, "Notes of Alexsandrov", one of the earliest autobiographies in the Russian language. To his outrage, publishers disregarded the chosen name and title, re-titling it "Notes of N.A. Durova", and eventually The Cavalry Maiden.

Historians have traditionally regarded him as a female wartime cross-dresser, while several modern scholars describe him as a transgender man.

Alexander Andreevich Alexandrov (named Nadezhda Andreyevna Durova), was born on 17 September 1783, into the family of a Russian major. Sources identify his birth place as either the Vyatka Governorate of the Russian Empire, an army camp in Kyiv, or Kherson. His mother came from a family of wealthy landowners from Poltava, and married his father against the will of his own father. According to Alexandrov, his mother "passionately wanted to have a son" and was dismayed to apparently have a daughter instead; he describes an incident in which she—furious at her infant for crying all night—threw him from the window of a moving carriage, nearly killing him. After that his father placed him in the care of his soldiers. As a child, Alexandrov learned the standard marching commands, and an unloaded gun was his favorite toy.

After his father retired from service, he continued playing with broken sabers and frightened his family by secretly taming a stallion that they considered unbreakable.

In 1801, he married a Sarapul judge, Vasily Stefanovich Chernov, a man seven years his senior. He gave birth to Chernov's son on 4 January 1803. On 17 September 1806, Alexandrov dressed in a Cossack uniform, abandoned home, and enlisted in the Polish Uhlan Regiment, presenting himself as a nobleman named Alexander Sokolov.

As "Alexander Sokolov", he fought in the major Russian engagements of the 1806–1807 Prussian campaign. During two of those battles, he saved the lives of two fellow Russian soldiers. The first was an enlisted man who suffered a concussion falling off his horse in battle. Alexandrov provided first aid under heavy fire, and brought him to safety as the army retreated around them. The second was an officer, unhorsed but uninjured. Three French dragoons were closing on him. Alexandrov couched his lance and scattered the enemy. Then, against regulations, he let the officer borrow his own horse to hasten his retreat, which left Alexandrov himself more vulnerable to attack.

During the campaign, he wrote to his family explaining his disappearance. They used their connections in a desperate attempt to locate him. Rumors of an Amazon warrior in the army reached Tsar Alexander I, who took a personal interest and summoned him to the palace at St. Petersburg, where he was awarded the Cross of St. George and promoted to cornet of the Mariupol Hussar Regiment. The tsar also granted him the surname "Alexandrov".