Civil disobedience is the active and professed refusal of a citizen to obey certain laws, demands, orders, or commands of a government (or any other authority). By some definitions, civil disobedience has to be nonviolent to be called "civil". Hence, civil disobedience is sometimes equated with peaceful protests or nonviolent resistance. Henry David Thoreau's essay Resistance to Civil Government, first published in 1849 and then published posthumously in 1866 as Civil Disobedience, popularized the term in the US, although the concept itself was practiced long before this work.

Various forms of civil disobedience have been used by prominent activists, such as American women's suffrage leader Susan B. Anthony in the late 19th century, Egyptian nationalist Saad Zaghloul during the 1910s, and Indian nationalist Mahatma Gandhi in 1920s British India as part of his leadership of the Indian independence movement. Martin Luther King Jr.'s and James Bevel's peaceful nonviolent protests during the civil rights movement in the 1960s United States sometimes contained important aspects of civil disobedience. Although civil disobedience is rarely justifiable in court, King regarded civil disobedience to be a display and practice of reverence for law: "Any man who breaks a law that conscience tells him is unjust and willingly accepts the penalty by staying in jail to arouse the conscience of the community on the injustice of the law is at that moment expressing the very highest respect for the law."

An early depiction of civil disobedience is in Sophocles' play Antigone, in which Antigone, one of the daughters of former King of Thebes, Oedipus, defies Creon, the current King of Thebes, who is trying to stop her from giving her brother Polynices a proper burial. She gives a stirring speech in which she tells him that she must obey her conscience rather than human law. She is not at all afraid of the death he threatens her with (and eventually carries out), but she is afraid of how her conscience will smite her if she does not do this.

Conrad Grebel and Anabaptists advocated civil disobedience to oppression. Étienne de La Boétie's thought developed in his work Discours de la servitude volontaire ou le Contr'un (1552) was also taken up by many movements of civil disobedience, which drew from the concept of rebellion to voluntary servitude the foundation of its instrument of struggle. Étienne de La Boétie was one of the first to theorize and propose the strategy of non-cooperation, and thus a form of nonviolent disobedience, as a really effective weapon.

In the lead-up to the Glorious Revolution in Britain—when the 1689 Bill of Rights was documented, the last Catholic monarch was deposed, and male and female joint-co-monarchs elevated—the English Midland Enlightenment developed a manner of voicing objection to a law viewed as illegitimate and then taking the consequences of the law. (For example, they might refuse to swear allegiance to the king, and, as a consequence, accept the prison sentence legally and normally meted out to people who refused to take this oath.) This was focused on the illegitimacy of laws claimed to be "divine" in origin, both the "divine rights of kings" and "divine rights of man", and the legitimacy of laws acknowledged to be made by human beings.^[relevant?]

Following the Peterloo massacre of 1819, the poet Percy Shelley wrote the political poem The Mask of Anarchy later that year, that begins with the images of what he thought to be the unjust forms of authority of his time—and then imagines the stirrings of a new form of social action. According to Ashton Nichols, it is perhaps the first modern statement of the principle of nonviolent protest. A version was taken up by the author Henry David Thoreau in his essay Civil Disobedience, and later by Gandhi in his doctrine of Satyagraha. Gandhi's Satyagraha was partially influenced and inspired by Shelley's nonviolence in protest and political action. In particular, it is known that Gandhi often quoted Shelley's Mask of Anarchy to vast audiences during the campaign for a free India.

Thoreau's 1849 essay Civil Disobedience, originally titled "Resistance to Civil Government", has had a wide influence on many later practitioners of civil disobedience. The driving idea behind the essay is that citizens are morally responsible for their support of aggressors, even when such support is required by law. In the essay, Thoreau explained his reasons for having refused to pay taxes as an act of protest against slavery and against the Mexican–American War. He writes,

If I devote myself to other pursuits and contemplations, I must first see, at least, that I do not pursue them sitting upon another man's shoulders. I must get off him first, that he may pursue his contemplations too. See what gross inconsistency is tolerated. I have heard some of my townsmen say, "I should like to have them order me out to help put down an insurrection of the slaves, or to march to Mexico;—see if I would go;" and yet these very men have each, directly by their allegiance, and so indirectly, at least, by their money, furnished a substitute.