Iaijutsu (居合術), often translated roughly as the "art of mental presence and immediate response", is the Japanese martial art of drawing the sword. At least one author makes the distinction that, strictly speaking, iaijutsu consists exclusively of the portion of combat where the sword is drawn, and that any further techniques are technically classified as kenjutsu.

It is unclear exactly when the term "iaijutsu" first came into use, or when exactly drawing the katana from its scabbard first became practiced as a discrete martial art; however, Iaijutsu was developed for the specific combative purpose of defending oneself, not on the battlefield, but in everyday life. A central feature of iaijutsu is, therefore, drawing the sword from several traditional sitting postures, including seiza, iai-goshi, and tate-hiza. Techniques from a standing posture (tachi-ai) are also studied. Additionally, with the emphasis upon defense during daily life, it was also generally assumed that combatants would be armed with a katana worn "edge-up" and thrust through a sash around the waist, and that combatants would be fighting unarmored. These assumptions result in a drastically different approach to combat than when combatants are armored and fighting on the battlefield.