diff --git a/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp
--- a/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp
@@ -62,7 +62,9 @@
                         ImplicitCastToNull,
                         hasAncestor(cxxRewrittenBinaryOperator().bind(
                             "checkBinopOperands")))
-                        .bind(CastSequence))))));
+                        .bind(CastSequence))),
+                // Skip defaulted comparison operators.
+                unless(hasAncestor(functionDecl(isDefaulted()))))));
 }
 
 bool isReplaceableRange(SourceLocation StartLoc, SourceLocation EndLoc,
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr-cxx20.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr-cxx20.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr-cxx20.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr-cxx20.cpp
@@ -1,9 +1,33 @@
 // RUN: %check_clang_tidy -std=c++20 %s modernize-use-nullptr %t
 
 namespace std {
+class strong_ordering;
+
+// Mock how STD defined unspecified parameters for the operators below.
+struct _CmpUnspecifiedParam {
+  consteval
+  _CmpUnspecifiedParam(int _CmpUnspecifiedParam::*) noexcept {}
+};
+
 struct strong_ordering {
-  int n;
-  constexpr operator int() const { return n; }
+  signed char value;
+
+  friend constexpr bool operator==(strong_ordering v,
+                                   _CmpUnspecifiedParam) noexcept {
+    return v.value == 0;
+  }
+  friend constexpr bool operator<(strong_ordering v,
+                                  _CmpUnspecifiedParam) noexcept {
+    return v.value < 0;
+  }
+  friend constexpr bool operator>(strong_ordering v,
+                                  _CmpUnspecifiedParam) noexcept {
+    return v.value > 0;
+  }
+  friend constexpr bool operator>=(strong_ordering v,
+                                   _CmpUnspecifiedParam) noexcept {
+    return v.value >= 0;
+  }
   static const strong_ordering equal, greater, less;
 };
 constexpr strong_ordering strong_ordering::equal = {0};
@@ -12,8 +36,10 @@
 } // namespace std
 
 class A {
+  int a;
 public:
   auto operator<=>(const A &other) const = default;
+  // CHECK-FIXES: auto operator<=>(const A &other) const = default;
 };
 
 void test_cxx_rewritten_binary_ops() {
@@ -32,3 +58,14 @@
   result = (a1 > ((a1 > (ptr == 0 ? a1 : a2)) ? a1 : a2));
   // CHECK-FIXES: result = (a1 > ((a1 > (ptr == nullptr ? a1 : a2)) ? a1 : a2));
 }
+
+template<class T1, class T2>
+struct P {
+  T1 x1;
+  T2 x2;
+  friend auto operator<=>(const P&, const P&) = default;
+  // CHECK-FIXES: friend auto operator<=>(const P&, const P&) = default;
+};
+
+bool foo(P<int,int> x, P<int, int> y) { return x < y; }
+// CHECK-FIXES: bool foo(P<int,int> x, P<int, int> y) { return x < y; }