Quantum field theories (QFTs) have been successfully applied to model and analyze diverse physical phenomena such as critical behavior in statistical mechanics and interactions of fundamental particles. However, except in special cases, the rigorous mathematical understanding of QFTs -- including fundamental questions about their very construction -- remains limited. This workshop aims to explore and develop the mathematical underpinnings of QFT from a probabilistic perspective. We will focus on current developments based on a detailed understanding of the Gaussian free field, viewpoints from random geometry, as well as recent advances on discrete models, including lattice gauge theories.