The Euston Manifesto ( YOO-stən) is a liberal conservative, pro-American, 2006 declaration of principles signed by a group of academics, journalists and activists based in the United Kingdom, named after the Euston Road in London where it had its meetings. The statement was a reaction to what the writers argued to be widespread violations of left-wing principles by others who were commonly associated with the Left. The manifesto states that "the reconfiguration of progressive opinion that we aim for involves drawing a line between forces on the Left that remain true to its authentic values, and currents that have lately shown themselves rather too flexible about these values".

The manifesto proposed a "fresh political alignment", which involves "making common cause with genuine democrats, whether socialist or not", in which the Left stands for democracy, freedom, equality, internationalism, the open-source movement and historical truth, while condemning all forms of tyranny, terrorism, anti-Americanism, racism and antisemitism, including any form of it that "conceal[s] prejudice against the Jewish people behind the formula of 'anti-Zionism'".

The signatories said they "reject fear of modernity, fear of freedom, irrationalism, the subordination of women", and

reaffirm the ideas that inspired the great rallying calls of the democratic revolutions of the eighteenth century: liberty, equality and solidarity; human rights; the pursuit of happiness ... But we are not zealots. For we embrace also the values of free enquiry, open dialogue and creative doubt, of care in judgement and a sense of the intractabilities of the world. We stand against all claims to a total — unquestionable or unquestioning — truth.