The effect of the war is shown through the relationships of five people's lives including the twin daughters of an influential businessman, a professor, a British expat, and a Nigerian houseboy.

Olanna has a twin sister, Kainene, a woman with a dry sense of humor, tired by the pompous company she runs for her father.

As a result of the conflict, Olanna, Odenigbo, their young daughter, whom they refer to only as "Baby", and Ugwu are forced to flee Nsukka, which is the university town and the major intellectual hub of the new nation.

They finally end up in the refugee town of Umuahia, where they suffer and struggle due to food shortages, the constant air raids and the environment of paranoia.

The Nigerian Civil War broke out due to political and ethnic struggles, partly caused by the numerous attempts of the southeastern provinces of Nigeria to secede and form the Republic of Biafra.

From 1968 onward, the war fell into a form of deadlock, with Nigerian forces unable to make significant advances into the remaining areas of Biafran control.

The Nigerian government cut off humanitarian aid to Biafra, resulting in hundreds of thousands of civilians dying from starvation and disease.

Many lives and resources were lost during the war, including Adichie's grandfathers; and even today there are still tensions between the different ethnic and religious groups of Nigeria.

[2][3] Half of a Yellow Sun centres on the war, and Adichie has said that important for her research was Buchi Emecheta's 1982 novel Destination Biafra.

One particularly noteworthy debate involves Odenigbo defending the tribe as the ideal unit for African, as other characters stress the need for pan-Africanism or nationalism.

Adichie herself has said in an interview, that "maybe [Richard's character] is my subtle way of slipping in my politics that maybe it's time that Africans wrote about Africa.

Although Half of a Yellow Sun does not have the conflict between a woman and patriarchy typical of feminist novels, it does show the agency of women.

Arize who is poor and uneducated, admires Olanna for postponing marriage but waits eagerly for a husband herself: "It is only women that know too much Book like you who can say that, Sister.

[9] In the November/December 2006 issue of Bookmarks, the book received a (4.5 out of 5) with the critical summary stating, "Drawing on her family’s experience and Nigeria’s history a decade before her birth, Adichie has written an ambitious, astonishing novel that succeeds on all levels".

[11] In a review for The Seattle Times, Mary Brennan called the book "a sweeping story that provides both a harrowing history lesson and an engagingly human narrative".

"[1] In Literary Review, William Brett wrote:  “Adichie lets the suspicion of horror take root first, and then allows it to sink in gradually.

This kind of subtlety makes reading her an extraordinary, unsettling but ultimately satisfying experience.”[13] The Washington Post states: “Chimamanda Ngozi Adichie certainly lives up to the hype in her second novel, Half a Yellow Sun.

While painting a searing portrait of the tragedy that took place in Biafra during the 1960s, her story finds its true heart in the intimacy of three ordinary lives buffeted by the winds of fate.

When an acquaintance of Olanna's turns up at a refugee camp, she notices that – he was thinner and lankier than she remembered and looked as though he would break in two if he sat down abruptly.

[18] In November 2020, Half of a Yellow Sun was voted the best book to have won the Women's Prize for Fiction in its 25-year history.

[20] In 2022, Half of a Yellow Sun was banned in the Hudsonville Public Schools district in Michigan due to the book's sexual and violent imagery.