This review focuses on the advancements in separators and membranes for advanced alkaline water electrolysis (AWE) and anion exchange membrane water electrolysis (AEMWE). Traditional AWE uses diaphragms to separate anode and cathode, typically operating with 5–7 M KOH feed solutions. The ban on asbestos diaphragms has led to the development of polymeric diaphragms, which are now the state-of-the-art material. Ion solvating membranes (ISMs) and AEMs are promising alternatives, offering high conductivities in 1 M KOH and improved stability, respectively. The review covers the following key areas: 1. **Poly(Phenylene Sulfide) Felts**: These are organic polymers with excellent chemical and thermal stability, used as separators in AWE. Challenges include hydrophobicity and gas crossover, which can be mitigated through surface treatments and composite materials. 2. **Zircon Type Diaphragms**: These are composite membranes made of polysulfone and zirconia particles, reinforced with PPS fibers. They improve wettability and gas transport compared to pure PPS felts. 3. **Ion Solvating Membranes**: PBI-based ISMs have shown high conductivities in 1 M KOH, but polymer degradation remains a challenge. Derivatives with electron-rich arylene linkages show improved stability. 4. **AEMs for Use in Alkaline Solutions < 2 M**: Recent advances in AEMs have improved performance in low-KOH solutions, addressing issues like anodic oxidation of the ionomer binder. 5. **Key Performance Indicators**: The review discusses various metrics for evaluating separator and membrane performance, including through-plane conductivity, hydroxide conductivity, hydrogen permeability, and mechanical strength. 6. **Design Strategies**: Future separators are expected to combine the benefits of different technologies, such as Zirfon-type diaphragms and ISMs, to achieve higher current densities and better stability. The review highlights the ongoing research and development in these areas, emphasizing the potential for AWE and AEMWE to become more similar in the future, driven by advancements in membrane and separator technologies.This review focuses on the advancements in separators and membranes for advanced alkaline water electrolysis (AWE) and anion exchange membrane water electrolysis (AEMWE). Traditional AWE uses diaphragms to separate anode and cathode, typically operating with 5–7 M KOH feed solutions. The ban on asbestos diaphragms has led to the development of polymeric diaphragms, which are now the state-of-the-art material. Ion solvating membranes (ISMs) and AEMs are promising alternatives, offering high conductivities in 1 M KOH and improved stability, respectively. The review covers the following key areas: 1. **Poly(Phenylene Sulfide) Felts**: These are organic polymers with excellent chemical and thermal stability, used as separators in AWE. Challenges include hydrophobicity and gas crossover, which can be mitigated through surface treatments and composite materials. 2. **Zircon Type Diaphragms**: These are composite membranes made of polysulfone and zirconia particles, reinforced with PPS fibers. They improve wettability and gas transport compared to pure PPS felts. 3. **Ion Solvating Membranes**: PBI-based ISMs have shown high conductivities in 1 M KOH, but polymer degradation remains a challenge. Derivatives with electron-rich arylene linkages show improved stability. 4. **AEMs for Use in Alkaline Solutions < 2 M**: Recent advances in AEMs have improved performance in low-KOH solutions, addressing issues like anodic oxidation of the ionomer binder. 5. **Key Performance Indicators**: The review discusses various metrics for evaluating separator and membrane performance, including through-plane conductivity, hydroxide conductivity, hydrogen permeability, and mechanical strength. 6. **Design Strategies**: Future separators are expected to combine the benefits of different technologies, such as Zirfon-type diaphragms and ISMs, to achieve higher current densities and better stability. The review highlights the ongoing research and development in these areas, emphasizing the potential for AWE and AEMWE to become more similar in the future, driven by advancements in membrane and separator technologies.