Whilst a student in Melbourne, Singer campaigned against the Vietnam War as president of the Melbourne University Campaign Against Conscription.
He also spoke publicly for the legalisation of abortion in Australia.

Singer joined the Australian Labor Party in 1974, but resigned after disillusionment with the centrist leadership of Bob Hawke.
In 1992, he became a founding member of the Victorian Greens.
He has run for political office twice for the Greens: in 1994 he received 28% of the vote in the Kooyong by-election, and in 1996 he received 3% of the vote when running for the Senate (elected by proportional representation).
Before the 1996 election, he co-authored a book The Greens with Bob Brown.

In A Darwinian Left, Singer outlines a plan for the political left to adapt to the lessons of evolutionary biology.
He says that evolutionary psychology suggests that humans naturally tend to be self-interested.
He further argues that the evidence that selfish tendencies are natural must not be taken as evidence that selfishness is "right."
He concludes that game theory (the mathematical study of strategy) and experiments in psychology offer hope that self-interested people will make short-term sacrifices for the good of others, if society provides the right conditions.
Essentially, Singer claims that although humans possess selfish, competitive tendencies naturally, they have a substantial capacity for cooperation that also has been selected for during human evolution.
Singer's writing in Greater Good magazine, published by the Greater Good Science Center of the University of California, Berkeley, includes the interpretation of scientific research into the roots of compassion, altruism, and peaceful human relationships.

Singer has criticised the United States for receiving "oil from countries run by dictators .... who pocket most of the" financial gains, thus "keeping the people in poverty."
Singer believes that the wealth of these countries "should belong to the people" within them rather than their "de facto government.
In paying dictators for their oil, we are in effect buying stolen goods, and helping to keep people in poverty."
Singer holds that America "should be doing more to assist people in extreme poverty".
He is disappointed in U.S. foreign aid policy, deeming it "a very small proportion of our GDP, less than a quarter of some other affluent nations."
Singer maintains that little "private philanthropy from the U.S." is "directed to helping people in extreme poverty, although there are some exceptions, most notably, of course, the Gates Foundation."

Singer describes himself as not anti-capitalist, stating in a 2010 interview with the New Left Project:
Capitalism is very far from a perfect system, but so far we have yet to find anything that clearly does a better job of meeting human needs than a regulated capitalist economy coupled with a welfare and health care system that meets the basic needs of those who do not thrive in the capitalist economy.

He added that "[i]f we ever do find a better system, I'll be happy to call myself an anti-capitalist".

Similarly, in his book Marx, Singer is sympathetic to Marx's criticism of capitalism, but is skeptical about whether a better system is likely to be created, writing: "Marx saw that capitalism is a wasteful, irrational system, a system which controls us when we should be controlling it.
That insight is still valid; but we can now see that the construction of a free and equal society is a more difficult task than Marx realised."

Singer is opposed to the death penalty, claiming that it does not effectively deter the crimes for which it is the punitive measure, and that he cannot see any other justification for it.

In 2010, Singer signed a petition renouncing his right of return to Israel, because it is "a form of racist privilege that abets the colonial oppression of the Palestinians."
Whilst a student in Melbourne, Singer campaigned against the Vietnam War as president of the Melbourne University Campaign Against Conscription. He also spoke publicly for the legalisation of abortion in Australia.
Singer joined the Australian Labor Party in 1974, but resigned after disillusionment with the centrist leadership of Bob Hawke. In 1992, he became a founding member of the Victorian Greens. He has run for political office twice for the Greens: in 1994 he received 28% of the vote in the Kooyong by-election, and in 1996 he received 3% of the vote when running for the Senate (elected by proportional representation). Before the 1996 election, he co-authored a book The Greens with Bob Brown.
In A Darwinian Left, Singer outlines a plan for the political left to adapt to the lessons of evolutionary biology. He says that evolutionary psychology suggests that humans naturally tend to be self-interested. He further argues that the evidence that selfish tendencies are natural must not be taken as evidence that selfishness is "right." He concludes that game theory (the mathematical study of strategy) and experiments in psychology offer hope that self-interested people will make short-term sacrifices for the good of others, if society provides the right conditions. Essentially, Singer claims that although humans possess selfish, competitive tendencies naturally, they have a substantial capacity for cooperation that also has been selected for during human evolution. Singer's writing in Greater Good magazine, published by the Greater Good Science Center of the University of California, Berkeley, includes the interpretation of scientific research into the roots of compassion, altruism, and peaceful human relationships.
Singer has criticised the United States for receiving "oil from countries run by dictators .... who pocket most of the" financial gains, thus "keeping the people in poverty." Singer believes that the wealth of these countries "should belong to the people" within them rather than their "de facto government. In paying dictators for their oil, we are in effect buying stolen goods, and helping to keep people in poverty." Singer holds that America "should be doing more to assist people in extreme poverty". He is disappointed in U.S. foreign aid policy, deeming it "a very small proportion of our GDP, less than a quarter of some other affluent nations." Singer maintains that little "private philanthropy from the U.S." is "directed to helping people in extreme poverty, although there are some exceptions, most notably, of course, the Gates Foundation."
Singer describes himself as not anti-capitalist, stating in a 2010 interview with the New Left Project:
Capitalism is very far from a perfect system, but so far we have yet to find anything that clearly does a better job of meeting human needs than a regulated capitalist economy coupled with a welfare and health care system that meets the basic needs of those who do not thrive in the capitalist economy.
He added that "[i]f we ever do find a better system, I'll be happy to call myself an anti-capitalist".
Similarly, in his book Marx, Singer is sympathetic to Marx's criticism of capitalism, but is skeptical about whether a better system is likely to be created, writing: "Marx saw that capitalism is a wasteful, irrational system, a system which controls us when we should be controlling it. That insight is still valid; but we can now see that the construction of a free and equal society is a more difficult task than Marx realised."
Singer is opposed to the death penalty, claiming that it does not effectively deter the crimes for which it is the punitive measure, and that he cannot see any other justification for it.
In 2010, Singer signed a petition renouncing his right of return to Israel, because it is "a form of racist privilege that abets the colonial oppression of the Palestinians."
Peter Singer