A novel tri-band bandpass filter (BPF) based on multi-mode resonators is pre- sented. The resonant modes of the resonators can be analyzed by the even- and odd-mode analysis method. The bandwidths of first and second passbands can be independently controlled. Furthermore, five transmission zeros (TZ) are introduced at the adjacent of the passbands in a narrow frequency range to improve the selectivity, resulting sharp skirts. Due to the small multi-mode resonator and tight coupling structure, the overall size of the proposed filter is re- ally compact (0.19λ0 × 0.18λ0 ). λ0 is the wavelength of the center frequency of first passband in the substrate. Finally, a prototype to demonstrate the performance of the filter is designed and fabricated. The measured 3-dB fractional bandwidths for the three passbands (2.22, 2.98 and 3.5 GHz) are found to be 8.4%, 2.7% and 6.1%, respectively. The measurement shows good agreement with the simulation.