In this letter, we present the design and fabrication in metallic 3-D printing of a compact conformal slotted waveguide antenna array (CSWAA) operating in the Ku-band. The application objective, although not limited only to this, is the optimization of an antenna element which by stacking will be able to form a quasi-cylindrical sector. A beamforming network will be used for beam steering in the elevation plane as coverage in the azimuthal plane is guaranteed by the conformal geometry. The compact design of the antenna element is, therefore, of great significance. For this reason, a direct feeding scheme by a coaxial connector is adopted. The antenna has been optimized following multiple parameteric analyses of its geometrical parameters for the enhancement of the bandwidth, return losses, and realized gain. The antenna was fabricated with selective laser melting in aluminum and the experimental results agree well with the numerically calculated ones. The proposed CSWAA exhibits a reflection coefficient below −10 dB, realized gain above 14 dBi, as well as good cross-polarization and side-lobe level over a relative bandwidth of 8%.