OP1

OP1 or OP-1 may refer to:


 * Opus number 1
 * Op. 1 (disambiguation), a list of compositions that are assigned this number
 * Bone morphogenetic protein 7 or BMP7, also known as osteogenic protein-1 or OP-1
 * Pitcairn OP-1, a first rotary-wing aircraft
 * Teenage Engineering OP-1, a portable synthesizer
 * a clade in the Branching order of bacterial phyla (Rappe and Giovanoni, 2003)
 * Rockchip RK3399, a Rockchip processor used in Chromebooks, marketed as OP1
 * OP1 grade tea, see
 * OP1, the highest possible Overall Position (OP) that high school graduates can receive in Queensland, Australia