Index: flang/lib/Semantics/check-omp-structure.h
===================================================================
--- flang/lib/Semantics/check-omp-structure.h
+++ flang/lib/Semantics/check-omp-structure.h
@@ -162,8 +162,10 @@
   void Enter(const parser::OmpReductionClause &);
   void Enter(const parser::OmpScheduleClause &);
 
-private:
+  void CheckIntentInPointer(
+      const parser::Name &, const Symbol &, const llvm::omp::Clause);
 
+private:
   bool HasInvalidWorksharingNesting(
       const parser::CharBlock &, const OmpDirectiveSet &);
 
Index: flang/lib/Semantics/check-omp-structure.cpp
===================================================================
--- flang/lib/Semantics/check-omp-structure.cpp
+++ flang/lib/Semantics/check-omp-structure.cpp
@@ -407,8 +407,28 @@
   CheckAllowed(llvm::omp::Clause::OMPC_priority);
   RequiresPositiveParameter(llvm::omp::Clause::OMPC_priority, x.v);
 }
-void OmpStructureChecker::Enter(const parser::OmpClause::Private &) {
+void OmpStructureChecker::Enter(const parser::OmpClause::Private &x) {
   CheckAllowed(llvm::omp::Clause::OMPC_private);
+  // Pointers with the INTENT(IN) attribute may not appear in a private clause
+  for (const auto &ompObject : x.v.v) {
+    if (const auto *name{parser::Unwrap<parser::Name>(ompObject)}) {
+      if (const auto *symbol{name->symbol}) {
+        if (const auto *commonBlockDetails{
+                symbol->detailsIf<CommonBlockDetails>()}) {
+          for (const auto &object : commonBlockDetails->objects()) {
+            CheckIntentInPointer(
+                *name, *object, llvm::omp::Clause::OMPC_private);
+          }
+        } else {
+          if (const auto *hostAssocDetails{
+                  symbol->detailsIf<HostAssocDetails>()}) {
+            symbol = &hostAssocDetails->symbol();
+          }
+          CheckIntentInPointer(*name, *symbol, llvm::omp::Clause::OMPC_private);
+        }
+      }
+    }
+  }
 }
 void OmpStructureChecker::Enter(const parser::OmpClause::Safelen &x) {
   CheckAllowed(llvm::omp::Clause::OMPC_safelen);
@@ -617,6 +637,16 @@
   }
 }
 
+void OmpStructureChecker::CheckIntentInPointer(const parser::Name &name,
+    const Symbol &symbol, const llvm::omp::Clause clause) {
+  if (IsPointer(symbol) && IsIntentIn(symbol)) {
+    context_.Say(name.source,
+        "Pointer '%s' with the INTENT(IN) attribute may not appear in a "
+        "%s clause"_err_en_US,
+        symbol.name(), parser::ToUpperCaseLetters(getClauseName(clause).str()));
+  }
+}
+
 llvm::StringRef OmpStructureChecker::getClauseName(llvm::omp::Clause clause) {
   return llvm::omp::getOpenMPClauseName(clause);
 }
Index: flang/lib/Semantics/resolve-directives.cpp
===================================================================
--- flang/lib/Semantics/resolve-directives.cpp
+++ flang/lib/Semantics/resolve-directives.cpp
@@ -320,6 +320,9 @@
   Symbol *DeclareOrMarkOtherAccessEntity(Symbol &, Symbol::Flag);
   void CheckMultipleAppearances(
       const parser::Name &, const Symbol &, Symbol::Flag);
+  SymbolVector GetNamelistSymbols();
+  void CheckObjectInNamelist(
+      const parser::Name &, const Symbol &, Symbol::Flag);
 };
 
 template <typename T>
@@ -945,6 +948,9 @@
                 if (dataSharingAttributeFlags.test(ompFlag)) {
                   CheckMultipleAppearances(*name, *symbol, ompFlag);
                 }
+                if (privateDataSharingAttributeFlags.test(ompFlag)) {
+                  CheckObjectInNamelist(*name, *symbol, ompFlag);
+                }
                 if (ompFlag == Symbol::Flag::OmpAllocate) {
                   AddAllocateName(name);
                 }
@@ -1073,4 +1079,41 @@
   }
 }
 
+void OmpAttributeVisitor::CheckObjectInNamelist(
+    const parser::Name &name, const Symbol &symbol, Symbol::Flag ompFlag) {
+  auto namelistSymbols = GetNamelistSymbols();
+  if (!namelistSymbols.empty()) {
+    const auto *target{&symbol};
+    if (ompFlagsRequireNewSymbol.test(ompFlag)) {
+      if (const auto *details{symbol.detailsIf<HostAssocDetails>()}) {
+        target = &details->symbol();
+      }
+    }
+    auto it{std::find(namelistSymbols.begin(), namelistSymbols.end(), *target)};
+    if (it != namelistSymbols.end()) {
+      llvm::StringRef clauseName = "PRIVATE";
+      if (ompFlag == Symbol::Flag::OmpFirstPrivate)
+        clauseName = "FIRSTPRIVATE";
+      else if (ompFlag == Symbol::Flag::OmpLastPrivate)
+        clauseName = "LASTPRIVATE";
+      context_.Say(name.source,
+          "Variable '%s' in %s clause is used in NAMELIST statement"_err_en_US,
+          name.ToString(), clauseName.str());
+    }
+  }
+}
+
+SymbolVector OmpAttributeVisitor::GetNamelistSymbols() {
+  SymbolVector namelistSymbols;
+  const auto symbols{currScope().parent().GetSymbols()};
+  for (const auto &symbol : symbols) {
+    if (const auto *namelistDetail{symbol->detailsIf<NamelistDetails>()}) {
+      for (const auto &object : namelistDetail->objects()) {
+        namelistSymbols.emplace_back(*object);
+      }
+    }
+  }
+  return namelistSymbols;
+}
+
 } // namespace Fortran::semantics
Index: flang/test/Semantics/omp-private01.f90
===================================================================
--- /dev/null
+++ flang/test/Semantics/omp-private01.f90
@@ -0,0 +1,20 @@
+! RUN: %S/test_errors.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.15.3.3 private Clause
+! Pointers with the INTENT(IN) attribute may not appear in a private clause.
+
+subroutine omp_target(p)
+  integer :: a(10), b(10), c(10)
+  integer, pointer, intent(in) :: p
+
+  a = 10
+  b = 20
+
+  !ERROR: Pointer 'p' with the INTENT(IN) attribute may not appear in a PRIVATE clause
+  !$omp parallel private(p)
+  c = a + b + p
+  !$omp end parallel
+
+  print *, c
+
+end subroutine omp_target
Index: flang/test/Semantics/omp-private02.f90
===================================================================
--- /dev/null
+++ flang/test/Semantics/omp-private02.f90
@@ -0,0 +1,23 @@
+! RUN: %S/test_errors.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.15.3.3 private Clause
+! Pointers with the INTENT(IN) attribute may not appear in a private clause.
+
+subroutine omp_target(p)
+  integer :: a(10), b(10), c(10)
+  integer, pointer, intent(in) :: p
+
+  !ERROR: Dummy argument 'p' may not appear in a COMMON block
+  common /cmn/ c, p
+
+  a = 10
+  b = 20
+
+  !ERROR: Pointer 'p' with the INTENT(IN) attribute may not appear in a PRIVATE clause
+  !$omp parallel private(/cmn/)
+  c = a + b + p
+  !$omp end parallel
+
+  print *, c
+
+end subroutine omp_target
Index: flang/test/Semantics/omp-private03.f90
===================================================================
--- /dev/null
+++ flang/test/Semantics/omp-private03.f90
@@ -0,0 +1,20 @@
+! RUN: %S/test_errors.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.15.3.3 private Clause
+! Variables that appear in namelist statements may not appear in a private clause.
+
+program omp_target
+  integer :: a, b, c
+  namelist /mylist/ a, b, c
+
+  a = 5
+  b = 10
+
+  !ERROR: Variable 'a' in PRIVATE clause is used in NAMELIST statement
+  !$omp parallel private(a)
+  c = a+b
+  !$omp end parallel
+
+  write(*, mylist)
+
+end program omp_target