The Ogasawara-ryū (小笠原流 "Ogasawara school"?) is a traditional Japanese system of martial arts and etiquette, formalised and handed down by the Ogasawara clan.
The school was originally developed by Ogasawara Nagakiyo during the Kamakura period (1185–1333). It specialised in horsemanship (bajutsu), archery (kyujutsu), mounted archery (yabusame) and etiquette, with an emphasis on ceremonial and ritual practice. Nagakiyo was the first to be called Ogasawara after his own village and was from the Minamoto clan. His father, Minamoto Tomitsu was highly skilled in both literary and military arts. Due to his bravery during the suppression of the Taira Clan, he was given an honorary post.
During the reign of Ashikaga Takauji, the first Ashikaga shogun, Nagakiyo's descendant Ogasawara Sadamune (1292–1347) was given responsibility for maintaining correct etiquette at Takauji's court, giving the Ogasawara-ryū official sanction. Sadamune was a student of Seisetsu Shōhō (Ch'ing-cho Ch'eng-cheng) and incorporated Seisetsu's Zen practices into the school. Three generations after Sadamune, Ogasawara Nagahide wrote the first manual of courtly etiquette, the Sangi Itto in 1380, after inheriting his father's post. The Sangi Itto also contained the Ogasawara family's teachings on horsemanship and archery. Despite this, the martial aspects of the school's teaching were largely lost by the end of the Muromachi period (1573), and the school survived only as a system of courtly manners. The Ogasawara style of mounted archery was eventually revived in 1724 by Ogasawara Heibei Tsuneharu.