The invited session on Numerical Modeling of Welding, Joining, and Processing focuses on recent advances in computational methods for understanding, predicting, and optimizing manufacturing operations involving material joining and processing. Numerical modeling has become a key tool in engineering, enabling improved process efficiency, enhanced product quality, and reduced reliance on costly experimental trials. By simulating process parameters, heat transfer, and material behavior, these approaches provide valuable insight into weld pool evolution, phase transformations, residual stress development, and resulting mechanical and metallurgical properties. Welding, joining, and processing operations involve complex, strongly coupled physical phenomena, including melting and solidification, fluid flow, thermal and mass transport, microstructural evolution, and stress formation. Addressing these challenges requires robust multiphysics and multiscale modeling frameworks. Contributions are encouraged using a wide range of numerical techniques such as finite element and finite volume methods, smoothed particle hydrodynamics, Monte Carlo simulations, and phase-field approaches, enabling predictive capabilities across different spatial and temporal scales. The session covers a broad spectrum of technologies, including fusion welding, solid-state processes (such as friction stir and friction deposition), as well as brazing, soldering, adhesive bonding, mechanical joining, and other material processing techniques. Both fundamental modeling developments and industrial applications are welcome. Emerging data-driven approaches, including artificial intelligence, machine learning, and digital twin frameworks for process optimization, real-time monitoring, and control, are also of particular interest. Special emphasis is placed on the processing and joining of advanced and dissimilar materials, including lightweight alloys, polymers, and composite systems. The session aims to provide a platform for sharing state-of-the-art developments and fostering collaboration between academia and industry in the field of computational modeling of joining and processing technologies.