diff --git a/libcxx/src/new.cpp b/libcxx/src/new.cpp
--- a/libcxx/src/new.cpp
+++ b/libcxx/src/new.cpp
@@ -57,6 +57,11 @@
     !defined(_LIBCPP_ABI_VCRUNTIME) &&      \
     !defined(_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS)
 
+// Sanitizer runtimes provide their own definitions of new and delete operators.
+#if !__has_feature(address_sanitizer) && \
+    !__has_feature(hwaddress_sanitizer) && \
+    !__has_feature(thread_sanitizer)
+
 // Implement all new and delete operators as weak definitions
 // in this shared library, so that they can be overridden by programs
 // that define non-weak copies of the functions.
@@ -298,4 +303,5 @@
 }
 
 #endif // !_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
+#endif // !address_sanitizer && !hwaddress_sanitizer && !thread_sanitizer
 #endif // !__GLIBCXX__ && !_LIBCPP_ABI_VCRUNTIME && !_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS
diff --git a/libcxxabi/src/stdlib_new_delete.cpp b/libcxxabi/src/stdlib_new_delete.cpp
--- a/libcxxabi/src/stdlib_new_delete.cpp
+++ b/libcxxabi/src/stdlib_new_delete.cpp
@@ -17,6 +17,12 @@
 #error The _THROW_BAD_ALLOC, _NOEXCEPT, and _LIBCXXABI_WEAK libc++ macros must \
        already be defined by libc++.
 #endif
+
+// Sanitizer runtimes provide their own definitions of new and delete operators.
+#if !__has_feature(address_sanitizer) && \
+    !__has_feature(hwaddress_sanitizer) && \
+    !__has_feature(thread_sanitizer)
+
 // Implement all new and delete operators as weak definitions
 // in this shared library, so that they can be overridden by programs
 // that define non-weak copies of the functions.
@@ -259,4 +265,5 @@
     ::operator delete[](ptr, alignment);
 }
 
+#endif // !address_sanitizer && !hwaddress_sanitizer && !thread_sanitizer
 #endif // !_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION