This study investigates the temperature-dependent quasi-static magnetoelectric (ME) response (αE) of electrically poled lead-free Na 0.4 K 0.1 Bi 0.5 TiO 3 –NiFe 2 O 4 (NKBT–NFO)-laminated composites. The aim is to understand the temperature stability of ME-based sensors and devices. The relaxor ferroelectric nature of NKBT is confirmed through impedance and polarization–electric (PE) hysteresis loop studies, with a depolarization temperature ( T d ) of approximately 110 °C. Heating causes a decrease and disappearance of planar electromechanical coupling ( K p ), charge coefficient ( d 31 ), and remnant polarization ( P r ) above T d . The temperature rise to 125 °C also leads to a reduction in magnetostriction ( λ ) and magnetostriction coefficient ( q  = d λ /d H ) of NFO by approximately 33% and 25%, respectively. At room temperature, the bilayer and trilayer configurations exhibit maximum ME responses of approximately 33 mV/cm·Oe and 80 mV/cm·Oe, respectively, under low magnetic field conditions ( H ∼ 300–450 Oe). The ME response of NKBT/NFO is highly sensitive to temperature, decreasing with heating in accordance with the individual temperature-dependent properties of NKBT and NFO. This study demonstrates a temperature window for the effective utilization of NKBT/NFO-based laminated composite ME devices.