Isidore Marie Auguste François Xavier Comte (French: [oˈɡyst kɔ̃t] (listen); 19 January 1798 – 5 September 1857) was a French philosopher, mathematician and writer who formulated the doctrine of positivism. He is often regarded as the first philosopher of science in the modern sense of the term. Comte's ideas were also fundamental to the development of sociology; indeed, he invented the term and treated that discipline as the crowning achievement of the sciences.

Influenced by Henri de Saint-Simon, Comte's work attempted to remedy the social disorder caused by the French Revolution, which he believed indicated imminent transition to a new form of society. He sought to establish a new social doctrine based on science, which he labelled positivism. He had a major impact on 19th-century thought, influencing the work of social thinkers such as John Stuart Mill and George Eliot. His concept of Sociologie and social evolutionism set the tone for early social theorists and anthropologists such as Harriet Martineau and Herbert Spencer, evolving into modern academic sociology presented by Émile Durkheim as practical and objective social research.

Comte's social theories culminated in his "Religion of Humanity", which presaged the development of non-theistic religious humanist and secular humanist organisations in the 19th century. He may also have coined the word altruisme (altruism).