Critics praised the novel, especially noting its range across different societies and reflection of global tensions. Writing for The New York Times, Mike Peed said, "'Americanah' examines blackness in America, Nigeria and Britain, but it’s also a steady-handed dissection of the universal human experience—a platitude made fresh by the accuracy of Adichie’s observations." Peed concluded, “'Americanah' is witheringly trenchant and hugely empathetic, both worldly and geographically precise, a novel that holds the discomfiting realities of our times fearlessly before us. It never feels false." Reviewing the novel for The Washington Post, Emily Raboteau called Adichie "a hawkeyed observer of manners and distinctions in class," and said Adichie brings a "ruthless honesty about the ugly and beautiful sides of both" the United States and Nigeria. In the Chicago Tribune, Laura Pearson said, "Sprawling, ambitious and gorgeously written, 'Americanah' covers race, identity, relationships, community, politics, privilege, language, hair, ethnocentrism, migration, intimacy, estrangement, blogging, books and Barack Obama. It covers three continents, spans decades, leaps gracefully, from chapter to chapter, to different cities and other lives...[Adichie] weaves them assuredly into a thoughtfully structured epic. The result is a timeless love story steeped in our times."
The book was selected as one of the 10 Best Books of 2013 by the editors of the New York Times Book Review. It won the 2013 National Book Critics Circle Award (Fiction), and was shortlisted for the 2014 Baileys Women's Prize for Fiction of the United Kingdom. The Chicago Tribune awarded Adichie its 2013 Heartland Award for Fiction, "recogniz[ing Americanah as] a novel that engages with important ideas about race, and does so with style, wit and insight."
In March 2017, Americanah was picked as the winner for the "One Book, One New York" program, part of a community reading initiative encouraging all city residents to read the same book.
Americanah spent 78 weeks on NPR's Paperback Best-Seller list. Days after The New York Times named Americanah to its best books of 2013 list, Beyoncé also signaled her admiration of Adichie, sampling Adichie's TED Talk "We should all be feminists" on the song "***Flawless"; sales of Americanah soared and as of December 23, 2013, the book climbed to the number 179 spot on Amazon.com's list of its 10,000 best-selling books.