Herein, the structural, morphological, compositional, and electrical properties of SeO2 microwires are studied and analyzed. Microwires of SeO2 with dimensions of 460 ×  30 × 30  ( μ m )   3 are electrically characterized in the temperature range of 17–300 K. SeO2 microwires are observed exhibiting nanocrystalline structures relating to a tetragonal phase. The microwires contained excess oxygen leading to some Se vacancies. The current–voltage (I–V) characteristics of the microwires displayed temperature‐dependent abrupt switching property revealing an “ON/OFF” current ratio of ≈90 at a threshold voltage of 0.48 V at 300 K. These features of the microwires remained down to 250 K. In addition, the temperature‐dependent electrical resistivity measurement showed that the microwires perform as a degenerate (metal like) semiconductors with quadratic temperature dependence (ρ false( T false) ∝ T 2 ). Moreover, impedance spectra analysis has shown that SeO2 microwires exhibit negative resistance and negative dielectric constant effects in the spectral ranges of 20–1800 MHz. The work here indicates that SeO2 microwires can perform much better than powders in pellets form or in thin‐film form. The resonance–antiresonance of dielectric constant and abrupt switching properties are accounted as remarkable features of the SeO2 microwires nominating them as abrupt electronic switches and signal amplifiers at workable in microelectronics.