In linguistics, the augment was a syllable added to the beginning of the word in certain Indo-European languages, most notably Greek, Armenian, and the Indo-Iranian languages like Sanskrit, to form the perfect, preterite, or aorist tenses.

The augment survives and has been generalised in Modern Greek. For example, the verb ληγω, "I end," forms its aorist tense εληξα, "I ended." The initial ε represents the augment.

Philologists are uncertain whether the augment is a feature that was added to these branches of Indo-European, or whether the augment was present in the parent language and lost by all other branches save these.