Ethical intuitionism (also called moral intuitionism) is a view or family of views in moral epistemology (and, on some definitions, metaphysics). It is foundationalism applied to moral knowledge, the thesis that some moral truths can be known non-inferentially (i.e., known without one needing to infer them from other truths one believes). Such an epistemological view is by definition committed to the existence of knowledge of moral truths; therefore, ethical intuitionism implies cognitivism.

As a foundationalist epistemological position, ethical intuitionism contrasts with coherentist positions in moral epistemology, such as those that depend on reflective equilibrium.

Despite the name "ethical intuitionism", ethical intuitionists need not (though often do) accept that intuitions of value (or of evaluative facts) form the foundation of ethical knowledge; the common commitment of ethical intuitionists is to a non-inferential foundation for ethical knowledge, regardless of whether such a non-inferential foundation consists in intuitions as such.

Throughout the philosophical literature, the term "ethical intuitionism" is frequently used with significant variation in its sense. This article's focus on foundationalism reflects the core commitments of contemporary self-identified ethical intuitionists.

Sufficiently broadly defined, ethical intuitionism can be taken to encompass cognitivist forms of moral sense theory. It is usually furthermore taken as essential to ethical intuitionism that there be self-evident or a priori moral knowledge; this counts against considering moral sense theory to be a species of intuitionism. (see the Rational intuition versus moral sense section of this article for further discussion).