diff --git a/src/cryptography/utils.py b/src/cryptography/utils.py
index ef0fc4433..e0abd4a8a 100644
--- a/src/cryptography/utils.py
+++ b/src/cryptography/utils.py
@@ -49,16 +49,6 @@ def register_interface(iface):
     return register_decorator
 
 
-def register_interface_if(predicate, iface):
-    def register_decorator(klass, *, check_annotations=False):
-        if predicate:
-            verify_interface(iface, klass, check_annotations=check_annotations)
-            iface.register(klass)
-        return klass
-
-    return register_decorator
-
-
 def int_to_bytes(integer: int, length: typing.Optional[int] = None) -> bytes:
     return integer.to_bytes(
         length or (integer.bit_length() + 7) // 8 or 1, "big"
diff --git a/tests/test_interfaces.py b/tests/test_interfaces.py
index 89d802aed..7736690cb 100644
--- a/tests/test_interfaces.py
+++ b/tests/test_interfaces.py
@@ -8,33 +8,10 @@ import pytest
 
 from cryptography.utils import (
     InterfaceNotImplemented,
-    register_interface_if,
     verify_interface,
 )
 
 
-def test_register_interface_if_true():
-    class SimpleInterface(metaclass=abc.ABCMeta):
-        pass
-
-    @register_interface_if(1 == 1, SimpleInterface)
-    class SimpleClass(object):
-        pass
-
-    assert issubclass(SimpleClass, SimpleInterface) is True
-
-
-def test_register_interface_if_false():
-    class SimpleInterface(metaclass=abc.ABCMeta):
-        pass
-
-    @register_interface_if(1 == 2, SimpleInterface)
-    class SimpleClass(object):
-        pass
-
-    assert issubclass(SimpleClass, SimpleInterface) is False
-
-
 class TestVerifyInterface(object):
     def test_verify_missing_method(self):
         class SimpleInterface(metaclass=abc.ABCMeta):