diff --git a/sci-chemistry/openbabel/openbabel-3.1.1_p20241221-r2.ebuild b/sci-chemistry/openbabel/openbabel-3.1.1_p20241221-r2.ebuild
index 68911e4bf2864..35d8710c6fa3d 100644
--- a/sci-chemistry/openbabel/openbabel-3.1.1_p20241221-r2.ebuild
+++ b/sci-chemistry/openbabel/openbabel-3.1.1_p20241221-r2.ebuild
@@ -39,7 +39,7 @@ REQUIRED_USE="
 "
 
 RDEPEND="
-	dev-cpp/eigen:3
+	dev-cpp/eigen:=
 	virtual/zlib:=
 	inchi? ( sci-libs/inchi )
 	json? ( >=dev-libs/rapidjson-1.1.0 )
diff --git a/sci-chemistry/openbabel/openbabel-3.1.1_p20241221-r4.ebuild b/sci-chemistry/openbabel/openbabel-3.1.1_p20241221-r4.ebuild
index d72bc5da44d30..54f2ad8e15832 100644
--- a/sci-chemistry/openbabel/openbabel-3.1.1_p20241221-r4.ebuild
+++ b/sci-chemistry/openbabel/openbabel-3.1.1_p20241221-r4.ebuild
@@ -40,7 +40,7 @@ REQUIRED_USE="
 "
 
 RDEPEND="
-	dev-cpp/eigen:3
+	dev-cpp/eigen:=
 	virtual/zlib:=
 	inchi? ( sci-libs/inchi )
 	json? ( >=dev-libs/rapidjson-1.1.0 )
diff --git a/sci-chemistry/openbabel/openbabel-9999.ebuild b/sci-chemistry/openbabel/openbabel-9999.ebuild
index 064a3f75bd14b..76f22a9da12d5 100644
--- a/sci-chemistry/openbabel/openbabel-9999.ebuild
+++ b/sci-chemistry/openbabel/openbabel-9999.ebuild
@@ -40,7 +40,7 @@ REQUIRED_USE="
 "
 
 RDEPEND="
-	dev-cpp/eigen:3
+	dev-cpp/eigen:=
 	virtual/zlib:=
 	inchi? ( sci-libs/inchi )
 	json? ( >=dev-libs/rapidjson-1.1.0 )