法律解释是司法机构解读和运用成文法的过程。当案件涉及成文法时，法律条文经常必须经过一定的解读。有时法律条文的意义浅显直白，但许多时候条文所用字句的意义会在一定程度上稍有含糊或不确定，因此法庭必须决定条文的准确含义。在确定法律条文的意义的过程中，法庭使用各种法律解释的工具和方法，例如传统的法律解释原则、立法过程、以及立法目的。

在普通法系统中，司法机构运用法律解释的规则来解读立法机构所立的成文法，以及根据立法授权颁布的受权立法，例如行政机构的规章等。

在普通法系统和部分大陆法系法律系统中，由于立法权和司法权的分离，法律解释是司法机构独有的权力。但在一些国家，除了司法机构，立法机构或行政机构在法律颁布之后也拥有对法律的具体运用进行事后解释的权力。允许立法机构进行事后解释代表对立法机构意愿的最大尊重，即立法机构解释所立法律的具体运用可以推翻司法机构对法律的解读。这种解释在立法权和司法权分立的制度里是不允许的：这种解释行为更类似进一步的、具追溯效力的立法行为，是一种限制司法机构判断具体案例的行为，因此在许多国家是不允许的。而行政机构对法律进行解释一般必需在法律所授权的范围内进行，是一种受权立法行为。

Judicial interpretation is a theory or mode of thought that describes a general approach which the judiciary uses to interpret the law, particularly constitutional documents and legislation. This is a substantive issue in the United States to a greater extent than in other nations because the nation's highest court, the Supreme Court, has the power to overturn laws made by the legislature in a process called judicial review. In effect, the court can decide such matters as the legality of slavery as in the Dred Scott decision, desegregation as in the Brown v Board of Education decision, and abortion rights as in the Roe v Wade decision. As a result, how justices interpret the constitution, and the ways in which they approach this task, has a political aspect. Terms describing types of judicial interpretation can be ambiguous; for example, the term judicial conservatism can vary in meaning depending on what is trying to be "conserved". One can look at judicial interpretation along a continuum from judicial restraint to judicial activism, with various viewpoints along the continuum.