diff --git a/test/test_advancedcpp.py b/test/test_advancedcpp.py
index 2b79cf5d..0dc5432c 100644
--- a/test/test_advancedcpp.py
+++ b/test/test_advancedcpp.py
@@ -694,7 +694,7 @@ def test20_overload_order_with_proper_return(self):
         assert cppyy.gbl.overload_one_way().gime() == 1
         assert cppyy.gbl.overload_the_other_way().gime() == "aap"
 
-    @mark.xfail(run=not IS_CLANG_REPL, reason="Valgrind Clang-Repl")
+    @mark.xfail(run=not IS_CLANG_REPL, reason="Valgrind issue on Clang-Repl")
     def test21_access_to_global_variables(self):
         """Access global_variables_and_pointers"""
 
diff --git a/test/test_crossinheritance.py b/test/test_crossinheritance.py
index 0d288399..ac740397 100644
--- a/test/test_crossinheritance.py
+++ b/test/test_crossinheritance.py
@@ -336,7 +336,7 @@ def call(self):
         gc.collect()
         assert CB.s_count == 0 + start_count
 
-    @mark.xfail
+    @mark.xfail(run=IS_CLANG_REPL, reason="Crashes otherwise")
     def test11_python_in_make_shared(self):
         """Usage of Python derived objects with std::make_shared"""
 
diff --git a/test/test_doc_features.py b/test/test_doc_features.py
index 8d9a9ebc..7e4ba1e6 100644
--- a/test/test_doc_features.py
+++ b/test/test_doc_features.py
@@ -1165,6 +1165,7 @@ def test_fallbacks(self):
         assert CC.passT(2**64-1) == 2**64-1
         assert 'unsigned long long' in CC.passT.__doc__
 
+    @mark.xfail(run=not IS_CLANG_REPL, reason="Crashes otherwise")
     def test_callbacks(self):
         """Function callback example"""
 
diff --git a/test/test_lowlevel.py b/test/test_lowlevel.py
index 49d84082..1ac5094f 100644
--- a/test/test_lowlevel.py
+++ b/test/test_lowlevel.py
@@ -1,6 +1,6 @@
 import py, os, sys
 from pytest import raises, skip, mark
-from .support import setup_make, pylong, pyunicode, IS_WINDOWS, ispypy
+from .support import setup_make, pylong, pyunicode, IS_WINDOWS, ispypy, IS_CLANG_REPL
 
 currpath = py.path.local(__file__).dirpath()
 test_dct = str(currpath.join("datatypesDict"))
@@ -307,7 +307,6 @@ def test07_ctypes_pointer_types(self):
         val = ctd.set_void_ppm(ptr)
         assert ctd.freeit(ptr) == val
 
-    @mark.xfail(reason="Valgrind")
     def test08_ctypes_type_correctness(self):
         """If types don't match with ctypes, expect exceptions"""
 
@@ -370,7 +369,7 @@ def py2c(pyargs):
         with raises(TypeError):
             cppyy.gbl.ArrayOfCStrings.takes_array_of_cstrings(pyargs, len(pyargs))
 
-    @mark.xfail(reason="Valgrind")
+    @mark.xfail(run=False, reason="Valgrind")
     def test11_array_of_const_char_ref(self):
         """Test passting of const char**&"""