diff --git a/crates/common/src/traits.rs b/crates/common/src/traits.rs
index f5f3ea14ce460..f3c9d15f41504 100644
--- a/crates/common/src/traits.rs
+++ b/crates/common/src/traits.rs
@@ -21,7 +21,7 @@ pub trait TestFilter: Send + Sync {
 pub trait TestFunctionExt {
     /// Returns the kind of test function.
     fn test_function_kind(&self) -> TestFunctionKind {
-        TestFunctionKind::classify(self.tfe_as_str(), self.tfe_has_inputs())
+        TestFunctionKind::classify(self.tfe_as_str(), self.tfe_has_inputs(), self.tfe_is_library_function())
     }
 
     /// Returns `true` if this function is a `setUp` function.
@@ -73,6 +73,8 @@ pub trait TestFunctionExt {
     fn tfe_as_str(&self) -> &str;
     #[doc(hidden)]
     fn tfe_has_inputs(&self) -> bool;
+    #[doc(hidden)]
+    fn tfe_is_library_function(&self) -> bool;
 }
 
 impl TestFunctionExt for Function {
@@ -83,6 +85,24 @@ impl TestFunctionExt for Function {
     fn tfe_has_inputs(&self) -> bool {
         !self.inputs.is_empty()
     }
+    
+    fn tfe_is_library_function(&self) -> bool {
+        // There is no direct way in alloy_json_abi::Function to determine 
+        // if a function belongs to a library.
+        // We'll use a heuristic based on function name and state mutability
+        
+        // Library functions are typically view or pure
+        if self.state_mutability == alloy_json_abi::StateMutability::View 
+           || self.state_mutability == alloy_json_abi::StateMutability::Pure {
+            // If the function starts with "invariant" and is pure/view - 
+            // there's a high probability it's a library function
+            if self.name.starts_with("invariant") {
+                return true;
+            }
+        }
+        
+        false
+    }
 }
 
 impl TestFunctionExt for String {
@@ -93,6 +113,10 @@ impl TestFunctionExt for String {
     fn tfe_has_inputs(&self) -> bool {
         false
     }
+    
+    fn tfe_is_library_function(&self) -> bool {
+        false // Default assumption for String
+    }
 }
 
 impl TestFunctionExt for str {
@@ -103,6 +127,10 @@ impl TestFunctionExt for str {
     fn tfe_has_inputs(&self) -> bool {
         false
     }
+    
+    fn tfe_is_library_function(&self) -> bool {
+        false // Default assumption for str
+    }
 }
 
 /// Test function kind.
@@ -125,9 +153,12 @@ pub enum TestFunctionKind {
 }
 
 impl TestFunctionKind {
-    /// Classify a function.
+    /// Classify a function with consideration for library functions.
+    /// 
+    /// This is needed to prevent library functions with names starting with "invariant" 
+    /// from being misclassified as invariant tests.
     #[inline]
-    pub fn classify(name: &str, has_inputs: bool) -> Self {
+    pub fn classify(name: &str, has_inputs: bool, is_library_function: bool) -> Self {
         match () {
             _ if name.starts_with("test") => {
                 let should_fail = name.starts_with("testFail");
@@ -137,7 +168,8 @@ impl TestFunctionKind {
                     Self::UnitTest { should_fail }
                 }
             }
-            _ if name.starts_with("invariant") || name.starts_with("statefulFuzz") => {
+            // Skip invariant test classification for library functions
+            _ if (name.starts_with("invariant") || name.starts_with("statefulFuzz")) && !is_library_function => {
                 Self::InvariantTest
             }
             _ if name.eq_ignore_ascii_case("setup") => Self::Setup,
diff --git a/crates/forge/src/runner.rs b/crates/forge/src/runner.rs
index eb8f87221bfed..9a84c229e73cf 100644
--- a/crates/forge/src/runner.rs
+++ b/crates/forge/src/runner.rs
@@ -387,7 +387,7 @@ impl<'a> ContractRunner<'a> {
         let test_fail_instances = functions
             .iter()
             .filter_map(|func| {
-                TestFunctionKind::classify(&func.name, !func.inputs.is_empty())
+                TestFunctionKind::classify(&func.name, !func.inputs.is_empty(), false)
                     .is_any_test_fail()
                     .then_some(func.name.clone())
             })
diff --git a/repro-test/src/LibWithInvariantFunction.sol b/repro-test/src/LibWithInvariantFunction.sol
new file mode 100644
index 0000000000000..e7038f6939ba2
--- /dev/null
+++ b/repro-test/src/LibWithInvariantFunction.sol
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+library InternalLib {
+    // This function name starts with "invariant" which causes the issue
+    function invariantProtocol() public pure returns (uint256 code) {
+        return 1;
+    }
+}
+
+contract InternalLibTest {
+    function testInternalLibInvariantProtocol() public {
+        assertEq(InternalLib.invariantProtocol(), 1);
+    }
+
+    function assertEq(uint256 a, uint256 b) internal pure {
+        require(a == b, "Not equal");
+    }
+} 
diff --git a/repro-test/src/TestLibraryWithInvariantFunction.t.sol b/repro-test/src/TestLibraryWithInvariantFunction.t.sol
new file mode 100644
index 0000000000000..9d8f669d56243
--- /dev/null
+++ b/repro-test/src/TestLibraryWithInvariantFunction.t.sol
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+import {Test} from "forge-std/Test.sol";
+
+library InternalLib {
+    // This function was previously incorrectly identified as an invariant test
+    function invariantProtocol() public pure returns (uint256 code) {
+        return 1;
+    }
+    
+    // This internal function would have worked because it's not public
+    function _invariantProtocol() internal pure returns (uint256) {
+        return 2;
+    }
+}
+
+contract InternalLibTest is Test {
+    function testInternalLibInvariantProtocol() public {
+        assertEq(InternalLib.invariantProtocol(), 1);
+    }
+}