This paper presents a substrate-integrated-waveguide-fed (SIW-fed) wideband millimeter-wave filtering antenna based on advanced through-glass via (TGV) technology, developed using two stacked glass layers incorporating high-precision metal layers. Glass wafers with thicknesses of 0.23 mm and 0.5 mm are employed to achieve high-density interconnects and precise manufacturing. Utilizing slotted radiating patches, two radiation nulls are first generated on the lower side of the operating band. Additionally, a pair of parasitic patches and parasitic loops are designed to introduce two more radiation nulls, enhancing the suppression level in the stopband. The proposed antenna does not require supplementary filtering circuits and is characterized by a wide bandwidth and low profile. To validate the proposed structure and design concept, a prototype antenna has been designed, fabricated, and measured. It exhibits a −10 dB impedance bandwidth of 31.9–45.9 GHz (35.9%), with measured out-of-band suppression levels exceeding 18.5 dB and 19.1 dB for the lower and upper stopbands, respectively. The measured peak gain is 8.5 dBi at 42.8 GHz.