The Otoko Series ( 男シリーズ Otoko Shirīzu) is a tetralogy of Drama CDs released for Tengen Toppa Gurren Lagann. It presents a world where the cast of Tengen Toppa Gurren Lagann lives in modern-day Japan, most of them either in attendance of or staffing the Dai-Gurren Academy, dealing with the impending forcible take-over of Japan by America's Teppelin Foundation.

The four parts consist of: