Substantive may refer to:

In grammar:

• a noun substantive, now also called simply noun
• a verb substantive, a verb like English "be" when expressing existence (in contrast to use as a copula)

In law:

• a matter of substance as opposed to a matter of procedure
• substantive law as opposed to procedural law

Substantive may also refer to:

• something that exists in its own right
• In biochemistry, the ability of chemicals to be retained by skin or hair
• In diplomacy, matters or fields of greater importance (in contrast to ancillary issues)