A novel structure, namely the stubbed waveguide cavity (SWC), is introduced in this paper. The SWC consists of a main TE201 mode cavity which is loaded with a pair of E-plane waveguide stubs. The stubs behave as two embedded half-mode cavities supporting a TM110 and TE011 mode, respectively. Three poles and two transmission zeros can be controlled with high design flexibility by properly dimensioning the various structural design parameters. The SWC is particularly suitable for the implementation of symmetric transmission zeros extremely close to the passband edges. The experimental results of a K-band prototype prove the feasibility of this new waveguide cavity.