Liberal feminism, also called mainstream feminism, is a main branch of feminism defined by its focus on achieving gender equality through political and legal reform within the framework of liberal democracy and informed by a human rights perspective. It is often considered culturally progressive and economically center-right to center-left. As the oldest of the "Big Three" schools of feminist thought, liberal feminism has its roots in 19th century first-wave feminism seeking recognition of women as equal citizens, focusing particularly on women's suffrage and access to education, the effort associated with 19th century liberalism and progressivism. Liberal feminism "works within the structure of mainstream society to integrate women into that structure." Liberal feminism places great emphasis on the public world, especially laws, political institutions, education and working life, and considers the denial of equal legal and political rights as the main obstacle to equality. As such liberal feminists have worked to bring women into the political mainstream. Liberal feminism is inclusive and socially progressive, while broadly supporting existing institutions of power in liberal democratic societies, and is associated with centrism and reformism. Liberal feminism tends to be adopted by white middle-class women who do not disagree with the current social structure; Zhang and Rios found that liberal feminism with its focus on equality is viewed as the dominant and "default" form of feminism. Liberal feminism actively supports men's involvement in feminism and both women and men have always been active participants in the movement; progressive men had an important role alongside women in the struggle for equal political rights since the movement was launched in the 19th century.

Historically, liberal feminism largely grew out of and was often associated with social liberalism; the modern liberal feminist tradition notably includes both social liberal and social democratic streams, as well as many often diverging schools of thought such as equality feminism, social feminism, care-ethical liberal feminism, equity feminism, difference feminism, conservative liberal feminism, and liberal socialist feminism. Some forms of modern liberal feminism have been described as neoliberal feminism or "boardroom feminism". Liberal feminism is often closely associated with liberal internationalism. In many countries, particularly in the West but also in a number of secular states in the developing world, liberal feminism is associated with the concept of state feminism, and liberal feminism emphasizes constructive cooperation with the government and involvement in parliamentary and legislative processes to pursue reforms. Liberal feminism is also called "mainstream feminism", "reformist feminism", "egalitarian feminism", or historically "bourgeois feminism" (or bourgeois-liberal feminism), among other names. As one of the "Big Three" schools of feminist thought, liberal feminism is often contrasted with socialist/Marxist feminism and radical feminism: unlike them, liberal feminism seeks gradual social progress and equality on the basis of liberal democracy rather than a revolution or radical reordering of society. Liberal feminism and mainstream feminism are very broad terms, frequently taken to encompass all feminism that is not radical or revolutionary socialist/Marxist and that instead pursues equality through political, legal, and social reform within a liberal democratic framework. As such, liberal feminists may subscribe to a range of different feminist beliefs and political ideologies within the democratic spectrum from the centre-left to the centre-right.

Inherently pragmatic in orientation, liberal feminists have emphasized building far-reaching support for feminist causes among both women and men, and among the political centre, the government and legislatures. In the 21st century, liberal feminism has taken a turn toward an intersectional understanding of gender equality, and modern liberal feminists support LGBT rights as a core feminist issue. Liberal feminists typically support laws and regulations that promote gender equality and ban practices that are discriminatory towards women; mainstream liberal feminists, particularly those of a social democratic bent, often support social measures to reduce material inequality within a liberal democratic framework. While rooted in first-wave feminism and traditionally focused on political and legal reform, the broader liberal feminist tradition may include parts of subsequent waves of feminism, especially third-wave feminism and fourth-wave feminism. The sunflower and the color gold, taken to represent enlightenment, became widely used symbols of mainstream liberal feminism and women's suffrage from the 1860s, originally in the United States and later also in parts of Europe.

The specific term "liberal feminism" is fairly modern, but its political tradition is much older. "Feminism" became the dominant term in English for the struggle for women's rights in the late 20th century, around a century after the organized liberal women's rights movement came into existence, but most western feminist historians contend that all movements working to obtain women's rights should be considered feminist movements, even when they did not (or do not) apply the term to themselves.

Historically, the bourgeois women's rights movement—the predecessor of modern liberal feminism—was mainly contrasted with the working-class or "proletarian" women's movements, which eventually developed into called socialist and Marxist feminism. Since the 1960s, both liberal feminism and the "proletarian" or socialist/Marxist women's movements are also contrasted with radical feminism. Liberal feminism is usually included as one of the two, three, or four main traditions in the history of feminism.

Many liberal feminists embraced the term "feminism" in the 1970s or 1980s. However, some initially expressed scepticism towards the term. For example, the liberal feminist Norwegian Association for Women's Rights expressed scepticism towards the term "feminism" as late as 1980 because it could foster "unnecessary antagonism towards men"; however, they accepted the term some years later as it increasingly became the mainstream general term for the women's rights struggle in the western world.

Liberal feminism ultimately has historical roots in classical liberalism and was often associated with social liberalism from the late 19th century. The goal for liberal feminists beginning in the late 18th century was to gain suffrage for women with the idea that this would allow them to gain individual liberty. They were concerned with gaining freedom through equality, diminishing men's cruelty to women, and gaining opportunities to become full persons. They believed that no government or custom should prohibit the due exercise of personal freedom. Early liberal feminists had to counter the assumption that only white men deserved to be full citizens. Pioneers such as Mary Wollstonecraft, Judith Sargent Murray, and Frances Wright advocated for women's full political inclusion. In 1920, after nearly 50 years of intense activism, women were finally granted the right to vote and the right to hold public office in the United States, and in much of the Western world within a few decades before or a few decades after this time.

Liberal feminism was largely quiet in the United States for four decades after winning the vote. In the 1960s during the civil rights movement, liberal feminists drew parallels between systemic race discrimination and sex discrimination. Groups such as the National Organization for Women, the National Women's Political Caucus, and the Women's Equity Action League were all created at that time to further women's rights. In the U.S., these groups have worked, thus far unsuccessfully, for the ratification of the Equal Rights Amendment or "Constitutional Equity Amendment", in the hopes it will ensure that men and women are treated as equals under the law. Specific issues important to liberal feminists include but are not limited to reproductive rights and abortion access, sexual harassment, voting, education, fair compensation for work, affordable childcare, affordable health care, and bringing to light the frequency of sexual and domestic violence against women.