A cutting insert according to an embodiment of the present invention includes an upper surface; a lower surface; a side surface located between the upper surface and the lower surface; at least one concave part extending in a thickness direction in the side surface, and having one end thereof located at the upper surface; and a cutting edge which is located at an intersection region of the upper surface and the side surface, and is divided into a plurality of divided cutting edges with the at least one concave part interposed therebetween. The upper surface includes a first raised part located inwardly of the at least one concave part, and a plurality of second raised parts respectively located inwardly of the plurality of divided cutting edges. The plurality of the second raised parts are located inward compared to one end of the first raised part close to the cutting edge in a top view. A cutting tool including the cutting insert, and a method of manufacturing a machined product using the cutting tool are also provided.