湖沼学是水文地理学的分支，从化学、物理、水文、地质角度研究内陆水体，包括天然和人造的：湖、沼、塘、溪、河、湿地、地下水等。

欧洲文本的「湖沼学」大多源于希腊文「Λίμνη」（湖）、「λόγος」（知识）的合并，罗马化后变成「Limnology」等变体。

Limnology (/lɪmˈnɒlədʒi/ lim-NOL-ə-jee; from Greek λίμνη, limne, "lake" and λόγος, logos, "knowledge"), is the study of inland waters. It is often regarded as a division of ecology or environmental science. It covers the biological, chemical, physical, geological, and other attributes of all inland waters (running and standing waters, both fresh and saline, natural or man-made). This includes the study of lakes and ponds, rivers, springs, streams and wetlands. A more recent sub-discipline of limnology, termed landscape limnology, studies, manages, and conserves these aquatic ecosystems using a landscape perspective.