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The electrical and electromechanical responses of ~200 µm thick extruded nanocomposite films comprising of 4 wt.% and 5 wt.% multiwall carbon nanotubes mixed with polypropylene are investigated under an alternating current (AC) and compared to their direct current (DC) response. The AC electrical response to frequency (<i>f</i>) and strain (piezoimpedance) is characterized using two configurations, namely one that promotes resistive dominance (resistive configuration) and the other that promotes the permittivity/capacitive contribution (dielectric configuration). For the resistive configuration, the frequency response indicated a resistive–capacitive (RC) behavior (negative phase angle, <i>θ</i>), with a significant contribution of capacitance for frequencies of 10⁴ Hz and above, depending on the nanotube content. The piezoimpedance characterization in the resistive configuration yielded an increasing impedance modulus (|<i>Z</i>|) and an increasing (negative) value of <i>θ</i> as the strain increased. The piezoimpedance sensitivity at <i>f</i> = 10 kHz was ~30% higher than the corresponding DC piezoresistive sensitivity, yielding a sensitivity factor of 9.9 for |<i>Z</i>| and a higher sensitivity factor (~12.7) for <i>θ</i>. The dielectric configuration enhanced the permittivity contribution to impedance, but it was the least sensitive to strain.