Circuit design and modeling represent pivotal elements in the development and optimization of electronic systems, contributing significantly to technological progress and performance enhancement. This chapter emphasizes the crucial role of directed circuit modeling and simulation in identifying potential issues during the design phase, facilitating the incorporation of design modifications and countermeasures to improve yield. Notably, many design and simulation processes, supported by Electronic Design Automation (EDA), are characterized by manual, iterative, labor-intensive, and time-consuming procedures. The integration of automated learning strategies from Artificial Intelligence (AI) and Machine Learning (ML) into EDA tools has the potential to revolutionize chip performance, and turnaround time, and substantially reduce time and cost requirements. This chapter explores AI-assisted automated approaches for circuit design and modeling, encompassing both device-level and logic/circuit-level design considerations. It also examines the state of the art and the challenges and opportunities related to applying AI/ML techniques in circuit modeling.