Robert Armin (c. 1568 – 1615) was an English actor, and member of the Lord Chamberlain's Men. He became the leading comedy actor with the troupe associated with William Shakespeare following the departure of Will Kempe around 1600. Also a popular comic author, he wrote a comedy, The History of the Two Maids of More-clacke, as well as Foole upon Foole, A Nest of Ninnies (1608) and The Italian Taylor and his Boy.

Armin changed the part of the clown or fool from the rustic servingman turned comedian to that of a high-comedy domestic wit.

Armin was one of three children born to John Armyn II of King's Lynn, a tailor and friend to John Lonyson, a goldsmith also of King's Lynn. His brother, John Armyn III, was a merchant tailor in London. Armin did not take up his father's craft; instead, his father apprenticed him to Lonyson in the Goldsmiths' Company in 1581. Lonyson was the Master of Works at the Royal Mint in the Tower of London, a position of great responsibility. The arrangement moved Armin to a life and a social circle quite different from what he might have expected as a Norfolk tailor. Lonyson died in 1582, and the apprenticeship was transferred to another master. According to a tale preserved in Tarlton's Jests, Armin came to the attention of the Queen's jester Richard Tarlton. In the course of his duties, the story contends, Armin was sent to collect money from a lodger at Tarlton's inn. Frustrated by the man's refusal to pay, Armin wrote verses in chalk on the wall; Tarlton noticed and, approving their wit, wrote an answer in which he expressed a desire to take Armin as his apprentice. Though not corroborated, this anecdote is far from the least plausible in Tarlton's Jests. Influenced by Tarlton or not, Armin already had a literary reputation before he finished his apprenticeship in 1592. In 1590, his name is affixed to the preface of a religious tract, A Brief Resolution of the Right Religion. Two years later, both Thomas Nashe (in Strange News) and Gabriel Harvey (in Pierce's Supererogation) mention him as a writer of ballads; none of his work in this vein, however, is known to have survived.

At some point in the 1590s, Armin joined a company of players patronised by William Brydges, 4th Baron Chandos. With this company, about which little is known, he is presumed to have travelled from the western Midlands to East Anglia. The nature of his work for the company may be estimated from his parts in The History of the Two Maids of More-clacke. The preface to the 1609 quarto indicates that he played Blue John, a clown in the vein of Tarlton and Kempe; he also seems to have doubled in the role of Tutch, a witty fool of the type he later played in London. The late quarto is associated with a revival by the King's Revels Children, a short-lived troupe of boy players led by Nathan Field, but it was almost certainly written around 1597.

Little else is known precisely of Armin's time with Chandos's Men. A dedication to his patron's widow in 1604 suggests some personal acquaintance with the Brydges family; on the other hand, a reference in another work suggests he may have spent some time, like Kempe, as a solo performer. The pair of books Armin published around the turn of the century demonstrate a performer with an interest in his craft. Fool Upon Fool (1600, 1605; reissued in 1608 as A Nest of Ninnies), offers the wit of assorted natural fools, some of whom Armin knew personally. The same year he published Quips upon Questions, a collection of seemingly extemporaneous dialogues with his marotte, named by him Signor Truncheon. In this he demonstrates his style; instead of having a conversation with the audience, as Tarlton did, and entering into a battle of wits, he jests using multiple personas, improvised song, or by commenting on a person or event. Rather than exchanging words, he gave words freely. Armin reported in that work that on either Tuesday 25 December 1599, or Tuesday 1 January 1600, he would be travelling to Hackney to wait on his "right honourable good lord". This was possibly Baron Chandos, who may have been visiting Edward la Zouche, 11th Baron Zouche over the holidays, or more likely Edward de Vere, 17th Earl of Oxford who lived in Hackney.

The first editions of these two books were credited to "Clonnico de Curtanio Snuffe"—that is, to the "Clown of the Curtain". The 1605 edition changes "Curtain" to "Mundo" (that is, Globe); only in 1608 was he credited by name, though the earlier title pages would have sufficed to identify him for Londoners.

Another work of uncertain date (it was published in 1609) is The Italian Tailor and his Boy. A translation of a tale from Gianfrancesco Straparola, the subject matter may reflect his family background of tailors. He was a tailor's son, who paralleled in the Italian tailor's apprentice, and the ruby ring of the play's lore parallels the goldsmith apprentice.

Sutcliffe argues that Armin wrote a pamphlet published in 1599, A Pil to Purge Melancholie, on the grounds that it was published by the same press, mentions a clown with Armin's nickname, and contains verbal echoes of Two Maids of More-clacke.