Proportionality may refer to:

• Proportionality (mathematics), the special mathematical relationships of direct and inverse proportion between two variables
• Proportionality (physics)
• Proportionality (law), a legal principle under municipal law in which the punishment of a certain crime should be in proportion to the severity of the crime itself, and under international law an important consideration when assessing the military necessity of an attack on a military objective
• Proportionality (political maxim), a maxim which states that any layer of government should not take any action that exceeds that which is necessary to achieve the objective of government

Proportion redirects here. Proportion may refer to:

• Proportion (architecture) describes the relationships between elements of a design
• Body proportions, in art, are the study of relation of human body parts to each other and the whole
• Proportions, or geometric aspect ratio

Proportional redirects here. Proportional may refer to:

• Proportional (fair division) means that each of n players thinks that they received 1/n of the cake.
• A proportional control system is a type of linear feedback control system
• Proportional representation in electoral systems
• Proportional fonts

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