Shevek is a tall, thin Odinian physicist from the collectivist moon of Anarres. Raised primarily in a state dormitory, he possesses a strong independent streak that frequently puts him at odds with his peers and his society's demand for conformity. He travels to the capitalist planet Urras to share his scientific theories and study freely, hoping to break the centuries-long isolation between the two worlds.

Takver is an idealistic biologist who specializes in cultivating marine life to support Anarres's harsh, resource-scarce environment. Tall and swarthy with a highly intelligent face, she fully supports Shevek's desire to pursue his scientific passions. She values independent thought over rigid societal expectations and forms a lasting partnership with Shevek.

Bedap is a heavyset, square-faced Odinian who grows up alongside Shevek. He develops a deep skepticism toward the administrative systems of Anarres, arguing that public opinion functions as an unacknowledged, oppressive government. He eventually collaborates with Shevek to push back against societal stagnation.

Sabul is a stocky, unkempt physicist who holds significant authority at Anarres's premier scientific institute. Rather than innovating, he relies on translating foreign texts and leveraging his position to claim co-authorship on the work of younger scientists. He actively suppresses research that does not directly benefit his own reputation.

Tirin is a sensitive, vulnerable youth with a snub-nosed face. He writes a satirical play depicting an Urrasti struggling with Odinian customs, drawing severe public backlash. His artistic expression places him outside the boundaries of accepted behavior, leading to heavy social consequences.

Rulag is a tall, handsome woman and a devoted member of Anarres's administrative unit, the PDC. She prioritizes her professional duties over familial bonds, a common practice in Odinian society. She strictly adheres to orthodox collectivist views and resists efforts to change the system.

Efor is a fifty-year-old servant working for the university in A-Io. His weathered face reflects a life of poverty and hard labor. He remains highly guarded around his employer due to the pervasive surveillance present in the university guest rooms, but gradually shares the reality of lower-class life.

Saio Pae serves as an official agent of the Ioti government and acts as Shevek's primary escort. He maintains a pleasant, highly capable demeanor while actively working to monitor the visiting physicist and keep him isolated from the general public.

Chifoilisk is a visiting academic and covert agent from the socialist nation of Thu. He warns Shevek about the continuous surveillance conducted by his Ioti hosts and attempts to persuade the physicist to relocate to his home state to share his theories.

Oiie is an Urrasti professional who maintains a quiet, tightly guarded presence at work. At his modest suburban home, he relaxes into a more open, familial demeanor, providing Shevek with his first genuine look at Urrasti domestic life and family dynamics.

Demaere is Oiie's pale, dark-eyed sister-in-law. She operates under the assumption that Urrasti women hold secret power over men through social influence, a belief challenged by the physical power dynamics of her society.

Dr. Atro is an aging Urrasti physicist who deeply values his profession. He holds strong prejudices about the inherent superiority of the Cetian race and expects Shevek to keep scientific breakthroughs strictly within their control.

Dr. Kimoe is a medical professional from Urras who travels with Shevek during his space voyage. He serves as the Anarresti visitor's first direct introduction to Urrasti customs, inadvertently revealing his culture's deep-seated class and gender prejudices.

Palat is Shevek's father on the planet Anarres. Following Odinian customs, he lives separately from Shevek's mother and does not play a significant, daily role in his son's upbringing in the state nursery.

Sadik is the eldest daughter of Takver and Shevek. Raised on Anarres, she experiences periods of separation from her father due to the society's strict work-posting assignments, forcing her to adapt to an irregular family life.

Pilun is the second daughter born to Shevek and Takver. Growing up in a society that demands conformity, she faces difficulties in her school dormitory due to her parents' unconventional choices and political friction.