This paper provides a comprehensive review of hybrid membrane distillation (MD) systems, focusing on their integration with waste heat and renewable energy sources, as well as their application in treating concentrated solutions. MD is highlighted as an attractive separation process due to its ability to use low-grade thermal energy, reduce energy consumption, and improve water recovery rates. The review covers the fundamentals and configurations of MD, including direct contact membrane distillation (DCMD), air gap membrane distillation (AGMD), sweeping gas membrane distillation (SGMD), vacuum membrane distillation (VMD), and osmotic membrane distillation (OMD). It also discusses the integration of MD with renewable energy sources such as solar radiation, salt-gradient solar ponds, and geothermal energy, as well as with pressure-retarded osmosis (PRO), multi-effect distillation (MED), reverse osmosis (RO), crystallization, forward osmosis (FO), and bioreactors. The paper critically analyzes the performance and potential of these hybrid systems, emphasizing their advantages in reducing energy consumption, improving water recovery, and addressing environmental concerns. Finally, the authors suggest future research directions, including the development of novel membrane materials and the optimization of system performance to enhance commercial viability.This paper provides a comprehensive review of hybrid membrane distillation (MD) systems, focusing on their integration with waste heat and renewable energy sources, as well as their application in treating concentrated solutions. MD is highlighted as an attractive separation process due to its ability to use low-grade thermal energy, reduce energy consumption, and improve water recovery rates. The review covers the fundamentals and configurations of MD, including direct contact membrane distillation (DCMD), air gap membrane distillation (AGMD), sweeping gas membrane distillation (SGMD), vacuum membrane distillation (VMD), and osmotic membrane distillation (OMD). It also discusses the integration of MD with renewable energy sources such as solar radiation, salt-gradient solar ponds, and geothermal energy, as well as with pressure-retarded osmosis (PRO), multi-effect distillation (MED), reverse osmosis (RO), crystallization, forward osmosis (FO), and bioreactors. The paper critically analyzes the performance and potential of these hybrid systems, emphasizing their advantages in reducing energy consumption, improving water recovery, and addressing environmental concerns. Finally, the authors suggest future research directions, including the development of novel membrane materials and the optimization of system performance to enhance commercial viability.