The external oblique muscle (Musculus obliquus externus abdominis) is a broad, flat muscle, also referred to as part of the anterolateral abdominal muscle group. It is located on the superficial layer of the anterolateral part of the abdomen. Its origin is serrated, starting from the outer surfaces of the lower eight ribs, with the muscle fibers running obliquely downward and forward. The posterior fibers of the muscle extend downward to the anterior part of the iliac crest, while the upper and middle portions of the fibers transition into an aponeurosis that covers the front of the rectus abdominis and contributes to the anterior layer of the rectus sheath, ending at the midline of the abdomen, known as the linea alba.

The external oblique muscles are the oblique muscles that constrict the abdomen, extending from the lowest ribs to the midline at the front of the body. Here, they join into a thin but strong layer of fibrous tissue. These muscles assist the rectus abdominis and a deeper set of oblique muscles (the internal obliques) in maintaining the abdominal organs in their proper position. Together, they form a crucial part of the body's core, providing stability and support to the torso, facilitating movements such as twisting and bending, and playing a significant role in functions like breathing, coughing, and bowel movements.