Alternatives to general relativity are physical theories that attempt to describe the phenomenon of gravitation in competition with Einstein's theory of general relativity. There have been many different attempts at constructing an ideal theory of gravity. These attempts can be split into four broad categories based on their scope:

None of these alternatives to general relativity have gained wide acceptance.

General relativity has withstood many tests over a large range of mass and size scales. When applied to interpret astronomical observations, cosmological models based on general relativity introduce two components to the universe, dark matter and dark energy, the nature of which is currently an unsolved problem in physics. The many successful, high precision predictions of the standard model of cosmology has led astrophysicists to conclude it and thus general relativity will be the basis for future progress. However, dark matter is not supported by the standard model of particle physics, physical models for dark energy do not match cosmological data, and some cosmological observations are inconsistent. These issues have led to the study of alternative theories of gravity.

${\displaystyle c\;}$ is the speed of light, ${\displaystyle G\;}$ is the gravitational constant. "Geometric variables" are not used.

Latin indices go from 1 to 3, Greek indices go from 0 to 3. The Einstein summation convention is used.

${\displaystyle \eta _{\mu \nu }\;}$ is the Minkowski metric. ${\displaystyle g_{\mu \nu }\;}$ is a tensor, usually the metric tensor. These have signature (−,+,+,+).

Partial differentiation is written ${\displaystyle \partial _{\mu }\varphi \;}$ or ${\displaystyle \varphi _{,\mu }\;}$. Covariant differentiation is written ${\displaystyle \nabla _{\mu }\varphi \;}$ or ${\displaystyle \varphi _{;\mu }\;}$.

For comparison with alternatives, the formulas of General Relativity are: