Landslides represent a significant geological hazard in the Indian Himalayan region, particularly in the Northeastern Himalayas and Northwestern Himalayas, posing substantial risks to human settlements, infrastructure, and natural ecosystems. Understanding the complex interplay between hydrological factors, such as rainfall and groundwater, and their influence on landslide occurrences is imperative for effective mitigation strategies and disaster management in these vulnerable regions. Rainfall, characterized by its intensity, duration, and spatial distribution, plays a pivotal role in triggering landslides in the Indian Himalayas. The steep topography coupled with the monsoonal climate regime results in intense rainfall events, particularly during the monsoon season, which significantly increases the susceptibility of the region to landslides. Moreover, the variability of rainfall patterns across different seasons further exacerbates landslide risks, with prolonged wet periods leading to saturation of the soil and increased pore water pressure, ultimately culminating in slope instability and landslide occurrences. Groundwater dynamics also exert a profound influence on landslide susceptibility in the Indian Himalayan region. The complex interaction between geological formations, hydrogeological properties, and groundwater flow regimes influences the stability of slopes. Groundwater infiltration into the subsurface can weaken slope materials, reduce soil cohesion, and lubricate potential slip surfaces, thereby facilitating landslide initiation and propagation. Additionally, fluctuations in groundwater levels, influenced by seasonal variations in precipitation and land use practices, contribute to temporal variations in landslide occurrences. This chapter aims to provide a thorough resource for researchers and stakeholders working in or planning to work in the Indian Himalayas. It aims to underscore both the limitations and strengths inherent in current research endeavours. It also offers insights into the critical areas requiring urgent attention for advancing landslide risk reduction efforts in the region.