Writing for Marginal Revolution, George Mason University economics professor Alex Tabarrok described the book as "that rare beast, a hard-headed, soft-hearted proponent of saving the world."

[6] Sue Desmond-Hellmann, CEO of the Bill & Melinda Gates Foundation, reviewed the book favorably, concluding: "Getting in the habit of giving back is never a bad thing.

"[3][8] The book's website also quotes favorable blurbs from bioethicist and effective altruism proponent Peter Singer, Skype and Kazaa co-founder Jaan Tallinn, Center for Applied Rationality president and co-founder Julia Galef, business school professor Adam Grant, anti-aging researcher Aubrey de Grey, nanotechnology pioneer Eric Drexler, astronomer Martin Rees, and linguist and researcher Steven Pinker.

[9] Kate Grant, CEO of the Fistula Foundation, that had been discussed in the book, was critical of MacAskill's description of the organization's work, noting that it was outdated and misleading.

[11] A Boston Review Forum contribution on effective altruism by Paul Brest, former President of the William and Flora Hewlett Foundation published on July 1, 2015, called MacAskill's book an "excellent new book" and viewed it as a key part of a strategy to move the world in the direction of effective altruism.