The labor theories of value (LTV) are theories in economics according to which the true values of commodities are related to the labor needed to produce them.

There are many different accounts of labor value, with the common element that the "value" of an exchangeable good or service is, or ought to be, or tends to be, or can be considered as, equal or proportional to the amount of labor required to produce it (including the labor required to produce the raw materials and machinery used in production).

Different labor theories of value prevailed amongst classical economists through to the mid-19th century. It is especially associated with Adam Smith and David Ricardo. Since that time it is most often associated with Marxian economics; while among modern mainstream economists it is considered to be superseded by the marginal utility approach.