Greek love is a term originally used by classicists to describe the primarily homoerotic customs, practices, and attitudes of the ancient Greeks. It was frequently used as a euphemism for both homosexuality and pederasty. The phrase is a product of the enormous impact of the reception of classical Greek culture on historical attitudes toward sexuality, and its influence on art and various intellectual movements.

Following the work of philosopher Michel Foucault, the validity of an ancient Greek model for modern gay culture has been questioned. In his essay "Greek Love", Alastair Blanshard sees "Greek love" as "one of the defining and divisive issues in the homosexual rights movement."

As a phrase in Modern English and other modern European languages, "Greek love" refers to various (mostly homoerotic) practices as part of the Hellenic heritage reinterpreted by adherents such as Lytton Strachey; quotation marks are often placed on either or both words ("Greek" love, Greek "love", or "Greek love") to indicate that usage of the phrase is determined by context. It often serves as a "coded phrase" for pederasty, or to "sanitize" homosexual desire in historical contexts where it was considered unacceptable.

The German term griechische Liebe ("Greek love") appears in German literature between 1750 and 1850, along with socratische Liebe ("Socratic love") and platonische Liebe ("Platonic love") in reference to male–male attractions. Ancient Greece became a positive reference point by which homosexual men of a certain class and education could engage in discourse that might otherwise be taboo. In the early Modern period, a disjuncture was carefully maintained between idealized male eros in the classical tradition, which was treated with reverence, and sodomy, which was a term of contempt.

In his classic study Greek Homosexuality, Kenneth Dover states that the English nouns "a homosexual" and "a heterosexual" have no equivalent in the ancient Greek language. Dover claims that, there was no concept in ancient Greece equivalent to the modern conception of "sexual preference and that it was assumed that a person could have both hetero- and homosexual responses at different times. However, Hubbard disagrees with this model, stating that "Close examination of a range of ancient texts suggests, however, that some forms of sexual preference were, in fact, considered a distinguishing characteristic of individuals. Many texts even see such preferences as inborn qualities and thus “essential” aspects of human identity". Evidence for same-sex attractions and behaviors is more abundant for men than for women. The most common male–male relationship was paiderasteia, a socially-acknowledged institution in which a mature male (erastēs, the active lover) bonded with or mentored a teen-aged youth (eromenos, the passive lover, or pais, "boy" understood as an endearment and not necessarily a category of age ). Pederasty was both idealized and criticized in Ancient Greek literature and philosophy. Martin Litchfield West views Greek pederasty as "a substitute for heterosexual love, free contacts between the sexes being restricted by society".

Greek art and literature portray these relationships as sometimes erotic or sexual, or sometimes idealized, educational, non-consummated, or non-sexual. A distinctive feature of Greek male–male eros was its occurrence within a military setting, as with the Theban Band, though the extent to which homosexual bonds played a military role has been questioned.

Some Greek myths have been interpreted as reflecting the custom of paiderasteia, most notably the myth of Zeus kidnapping Ganymede to become his cupbearer in the Olympian symposium. The death of Hyacinthus is also frequently referenced as a pederastic myth.

The main Greek literary sources for Greek homosexuality are lyric poetry, Athenian comedy, the works of Plato and Xenophon, and courtroom speeches from Athens. Vase paintings from the 500s and 400s BCE depict courtship and sex between males.