diff --git a/Changelog.md b/Changelog.md
index 69559a41c..b302dc700 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Consider current machine architecture when generating platform tags for abi3
   wheels on linux in [#709](https://github.com/PyO3/maturin/pull/709)
 * Revert back to Rust 2018 edition in [#710](https://github.com/PyO3/maturin/pull/710)
+* Warn missing `cffi` package dependency in [#711](https://github.com/PyO3/maturin/pull/711)
 
 ## [0.12.2] - 2021-11-26
 
diff --git a/src/build_context.rs b/src/build_context.rs
index 46a367cc2..28ba445dd 100644
--- a/src/build_context.rs
+++ b/src/build_context.rs
@@ -464,6 +464,19 @@ impl BuildContext {
         let policy = self.auditwheel(None, &artifact, self.platform_tag)?;
         let (wheel_path, tag) = self.write_cffi_wheel(&artifact, policy.platform_tag())?;
 
+        // Warn if cffi isn't specified in the requirements
+        if !self
+            .metadata21
+            .requires_dist
+            .iter()
+            .any(|dep| dep.to_ascii_lowercase().starts_with("cffi"))
+        {
+            eprintln!(
+                "⚠️  Warning: missing cffi package dependency, please add it to pyproject.toml. \
+                e.g: `dependencies = [\"cffi\"]`. This will become an error."
+            );
+        }
+
         println!("📦 Built wheel to {}", wheel_path.display());
         wheels.push((wheel_path, tag));