The recent development of gate-voltage-controlled Josephson junctions (JJs) enables dynamic tuning of critical currents, unlocking new possibilities for superconducting circuit applications. We propose an extension to JoSIM, the open-source superconducting SPICE simulator, to incorporate models for gate-tunable Josephson junctions (GTJJs) based on recent experimental findings. By integrating voltage-dependent critical current dynamics, our model will enable circuit-level simulations of hybrid superconductor–semiconductor devices and nanobridge-based JJs. Inspired by recent advancements in gate-controlled superconductor–semiconductor hybrid junctions and gate-tunable nanobridge Josephson junctions, this work provides an essential tool for designing and optimizing tunable superconducting circuits, including voltage-controlled SQUIDs, cryogenic logic elements, and qubit control in superconducting quantum processors. The ability to modulate superconducting currents via gate voltage offers a new avenue for high-speed, low-power quantum computing architectures. Our approach ensures computational efficiency while maintaining accuracy, making JoSIM a valuable resource for advancing scalable, energy-efficient superconducting electronics. This contribution aligns with the growing need for software tools to model emerging superconducting and quantum computing technologies, bridging the gap between experimental breakthroughs and practical circuit design.