diff --git a/Makefile b/Makefile
index 6fd7d57..cd26695 100644
--- a/Makefile
+++ b/Makefile
@@ -138,8 +138,9 @@ deny: ## Perform a `cargo deny` check.
 	cargo deny --locked --all-features check all
 
 .PHONY: about
-about: ## Generate the `THIRD_PARTY_NOTICES.md` file.
-	cargo about generate -c .github/about.toml -o THIRD_PARTY_NOTICES.md .github/about.hbs --locked
+about: THIRD_PARTY_NOTICES.md ## Generate the `THIRD_PARTY_NOTICES.md` file.
+THIRD_PARTY_NOTICES.md: Cargo.lock Cargo.toml crates/*/Cargo.toml .github/about.toml .github/about.hbs
+	cargo about generate -c .github/about.toml -o $@ .github/about.hbs --locked
 
 .PHONY: check
 check: ## Check all crates and targets.