Microalgal-based processes are increasingly valued for their applications in environmental protection, bioenergy production, and food manufacturing. The cultivation stage is crucial, as it heavily influences the final product’s cost, thus impacting the commercial feasibility of microalgae in various industries. A deep understanding of how microalgae thrive under different environmental conditions is vital for optimizing biomass yield. This chapter offers an extensive review of key models that relate microalgal growth with chemical and physical environmental factors, providing critical insights for improving cultivation efficiency and productivity. The reviewed models are categorically grouped based on the specific environmental factor under analysis and their underlying conceptual frameworks. The inclusion of multiple-factor modeling adds depth to our understanding, offering a comprehensive perspective on the intricate relationships governing microalgal growth. These models can be effectively integrated with hydrodynamics simulations through Computational Fluid Dynamics (CFD). CFD has emerged as a compelling tool for assessing the variability of culture variables in diverse photobioreactor (PBR) geometries. This approach eliminates the need for expensive and time-consuming experimental work and contributes to a more efficient and streamlined research process. The coupling of hydrodynamics simulation with diverse models linking microalgal growth to environmental factors establishes a holistic framework for the complete and robust performance simulation of various PBR designs. By synergistically employing CFD and diverse growth models, researchers can gain valuable insights into the complex dynamics governing microalgal-based processes. This integrated approach enhances our understanding of microalgal growth in varying environmental conditions and paves the way for more informed and strategic decision-making in the design and optimization of PBRs. As microalgae continue to emerge as a pivotal player in sustainable solutions, this chapter contributes to advancing the knowledge base and methodologies crucial for harnessing their full potential across a spectrum of industrial applications.