Abstract: A wafer processing apparatus includes a first tube extending in a vertical direction, a second tube arranged in the first tube and defining a reaction chamber, the reaction chamber being configured to receive a boat that holds a plurality of wafers, first and second gas nozzles in the second tube, the first and second gas nozzles being configured to supply first and second reaction gases, respectively, and being spaced apart from each other along a circumferential direction of the second tube to define a central angle of at about 50° to about 130° with respect to a center of the second tube, and an exhaust portion configured to exhaust residual gas from the reaction chamber, the exhaust portion including an exhaust slit in the second tube and an exhaust space between the first tube and the second tube.