Note: Included in parentheses are the pronunciations of the characters' names; the accents denote the appropriate stress.
The hero of the play, Vanya (a nickname for "Ivan" that is analogous to "Jack" or "Johnny" in English) is a bitter, broken man who has wasted his life toiling on the estate of his brother-in-law, Serebryakov. He is consumed with his lost life and obsessed with what might have been—a prime object of this obsession being the elusive Yelena. He functions as the play's misanthrope, offering a number of humorous caricatures of those around him. He is thus privileged with a certain bitter insight even as his friends and acquaintances dismiss him.
Plagued by gout and rheumatism, the pompous and egotistical Serebryakov is a failed scholar, deeply embittered by the onset of old age. He finds himself detestable in his infirmity and bemoans his residence in the provinces and his tomb-like estate, tormented by the meaningless chatter and indifference of his family. Notably he is terrified by his brother-in-law Voynitsky, perhaps betraying some latent remorse at having exploited him for his livelihood. In any case, Serebryakov is quick to cover over tensions in the household and reassert his preeminence. Votnitsky names him his "bitterest enemy."
The professor's beautiful wife, Yelena (the Russian equivalent of the Greek "Helen") fascinates all the major characters of the play, causing them to abandon their duties and fall into idleness. Indeed, she is characterized throughout the play by her infectious idleness and lack of interest in any serious work. Raised in the St. Petersburg Conservatory, she sacrificed a budding music career to marry the aging Serebryakov, whom she does not love but remains bound to him by conscience, convention, and inertia. Like a number of the play's characters, she suffers from a certain sense of self-estrangement, understanding herself as an "incidental character" in her own life.
The play's brooding and deliberate philosopher, Astrov is an overworked country doctor who feels ruined by provincial life. He is almost always deep in introspection, finding himself numb to the world, unable to want and love, and dejected at the thought that he will be forgotten in the course of time. Continually described as "eccentric" and "strange," he nevertheless is something of a visionary in his passion for conversation, decrying the degeneration of the land and destructive impulse he finds in man and hoping to leave his legacy to future generations. According to critic Eugene Bristow, Astrov's name suggests the word for "stars," which Bristow perhaps simplistically reads as in keeping with his high moral purpose.
Serebryakov's daughter by his first marriage, Sonya is named after the Greek for wisdom ("sophia"), though one wonders if she is particularly wise. Gentle but homely, she has steadfastly given herself to the maintenance of the estate and pines hopelessly after the brooding Dr. Astrov amidst all her drudgery. Throughout the play, she will be quick to chastise those who would disrupt the household—her father in particular—and will joylessly rededicate herself to her toils at the end of the play.
Maria is Voynitsky's mother. She is still enthralled with the professor, and passes her days usually annotating pamphlets on various social issues. Voynitsky probably describes her best in Act I: as a woman with one eye "fastened on the grave" and the other fixed on "her books of learning for the dawn of a new life."
Nicknamed "Waffles" for his pockmarked face, Telegin is an impoverished landowner who works on the estate. He is largely a comic figure, pathetic in his love life, cowed by conflict in the household, and prone to make the occasional inappropriate interjections. He is also the play's on-stage musician, playing the guitar in a number of scenes.
Marina is a kind, elderly, and devout nurse. Apparently finding a beneficent sense of order in the monotonous life of the estate, she resents the disruption of routine that the others have brought to the household. She delivers religious platitudes throughout the play and offers comfort to a number of characters (Sonya, Astrov, Serbryakov, etc.).