Orography (from the Greek όρος, hill, γραφία, to write) is the study of the formation and relief of mountains, and can more broadly include hills, and any part of a region's elevated terrain. Orography (also known as oreography, orology or oreology) falls within the broader discipline of geomorphology.

Orography has a major impact on global climate, for instance the orography of East Africa substantially determines the strength of the Indian monsoon. In geoscientific models, such as general circulation models, orography defines the lower boundary of the model over land.^{[citation needed]}

When a river's tributaries or settlements by the river are listed in 'orographic sequence', they are in order from the highest (nearest the source of the river) to the lowest or mainstem (nearest the mouth).^{[citation needed]} This method of listing tributaries is similar to the Strahler Stream Order, where the headwater tributaries are listed as category = 1.

Orographic precipitation, also known as relief precipitation, is precipitation generated by a forced upward movement of air upon encountering a physiographic upland (see anabatic wind). This lifting can be caused by two mechanisms: