diff --git a/flang/docs/OpenACC.md b/flang/docs/OpenACC.md
--- a/flang/docs/OpenACC.md
+++ b/flang/docs/OpenACC.md
@@ -17,3 +17,4 @@
 * The end directive for combined construct can omit the `loop` keyword.
 * An `!$acc routine` with no parallelism clause is treated as if the `seq`
   clause was present.
+* `!$acc end loop` does not trigger a parsing error and is just ignored.
diff --git a/flang/include/flang/Parser/dump-parse-tree.h b/flang/include/flang/Parser/dump-parse-tree.h
--- a/flang/include/flang/Parser/dump-parse-tree.h
+++ b/flang/include/flang/Parser/dump-parse-tree.h
@@ -105,6 +105,7 @@
   NODE(parser, AccTileExpr)
   NODE(parser, AccTileExprList)
   NODE(parser, AccLoopDirective)
+  NODE(parser, AccEndLoop)
   NODE(parser, AccWaitArgument)
   static std::string GetNodeName(const llvm::acc::Directive &x) {
     return llvm::Twine(
diff --git a/flang/include/flang/Parser/parse-tree.h b/flang/include/flang/Parser/parse-tree.h
--- a/flang/include/flang/Parser/parse-tree.h
+++ b/flang/include/flang/Parser/parse-tree.h
@@ -4244,11 +4244,10 @@
 };
 
 // OpenACC directives enclosing do loop
+EMPTY_CLASS(AccEndLoop);
 struct OpenACCLoopConstruct {
   TUPLE_CLASS_BOILERPLATE(OpenACCLoopConstruct);
-  OpenACCLoopConstruct(AccBeginLoopDirective &&a)
-      : t({std::move(a), std::nullopt}) {}
-  std::tuple<AccBeginLoopDirective, std::optional<DoConstruct>> t;
+  std::tuple<AccBeginLoopDirective, DoConstruct, std::optional<AccEndLoop>> t;
 };
 
 struct OpenACCStandaloneConstruct {
diff --git a/flang/lib/Parser/openacc-parsers.cpp b/flang/lib/Parser/openacc-parsers.cpp
--- a/flang/lib/Parser/openacc-parsers.cpp
+++ b/flang/lib/Parser/openacc-parsers.cpp
@@ -150,8 +150,13 @@
 TYPE_PARSER(construct<AccBeginLoopDirective>(
     sourced(Parser<AccLoopDirective>{}), Parser<AccClauseList>{}))
 
-TYPE_PARSER(
-    construct<OpenACCLoopConstruct>(sourced(Parser<AccBeginLoopDirective>{})))
+TYPE_PARSER(construct<AccEndLoop>(startAccLine >> "END LOOP"_tok))
+
+TYPE_PARSER(construct<OpenACCLoopConstruct>(
+    sourced(Parser<AccBeginLoopDirective>{} / endAccLine),
+    withMessage("A DO loop must follow the loop construct"_err_en_US,
+        Parser<DoConstruct>{}),
+    maybe(Parser<AccEndLoop>{} / endAccLine)))
 
 // 2.15.1 Routine directive
 TYPE_PARSER(sourced(construct<OpenACCRoutineConstruct>(verbatim("ROUTINE"_tok),
diff --git a/flang/lib/Parser/unparse.cpp b/flang/lib/Parser/unparse.cpp
--- a/flang/lib/Parser/unparse.cpp
+++ b/flang/lib/Parser/unparse.cpp
@@ -1947,7 +1947,7 @@
     Walk(std::get<AccBeginLoopDirective>(x.t));
     Put("\n");
     EndOpenACC();
-    Walk(std::get<std::optional<DoConstruct>>(x.t));
+    Walk(std::get<DoConstruct>(x.t));
   }
   void Unparse(const AccBeginLoopDirective &x) {
     Walk(std::get<AccLoopDirective>(x.t));
diff --git a/flang/lib/Semantics/canonicalize-acc.cpp b/flang/lib/Semantics/canonicalize-acc.cpp
--- a/flang/lib/Semantics/canonicalize-acc.cpp
+++ b/flang/lib/Semantics/canonicalize-acc.cpp
@@ -52,7 +52,8 @@
   // If there are n tile sizes in the list, the loop construct must be
   // immediately followed by n tightly-nested loops.
   template <typename C, typename D>
-  void CheckTileClauseRestriction(const C &x) {
+  void CheckTileClauseRestriction(
+      const C &x, const parser::DoConstruct &outer) {
     const auto &beginLoopDirective = std::get<D>(x.t);
     const auto &accClauseList =
         std::get<parser::AccClauseList>(beginLoopDirective.t);
@@ -63,11 +64,10 @@
         const std::list<parser::AccTileExpr> &listTileExpr = tileExprList.v;
         std::size_t tileArgNb = listTileExpr.size();
 
-        const auto &outer{std::get<std::optional<parser::DoConstruct>>(x.t)};
-        if (outer->IsDoConcurrent()) {
+        if (outer.IsDoConcurrent()) {
           return; // Tile is not allowed on DO CONCURRENT
         }
-        for (const parser::DoConstruct *loop{&*outer}; loop && tileArgNb > 0;
+        for (const parser::DoConstruct *loop{&outer}; loop && tileArgNb > 0;
              --tileArgNb) {
           const auto &block{std::get<parser::Block>(loop->t)};
           const auto it{block.begin()};
@@ -89,9 +89,9 @@
   // A tile and collapse clause may not appear on loop that is associated with
   // do concurrent.
   template <typename C, typename D>
-  void CheckDoConcurrentClauseRestriction(const C &x) {
-    const auto &doCons{std::get<std::optional<parser::DoConstruct>>(x.t)};
-    if (!doCons->IsDoConcurrent()) {
+  void CheckDoConcurrentClauseRestriction(
+      const C &x, const parser::DoConstruct &doCons) {
+    if (!doCons.IsDoConcurrent()) {
       return;
     }
     const auto &beginLoopDirective = std::get<D>(x.t);
@@ -109,73 +109,36 @@
 
   void RewriteOpenACCLoopConstruct(parser::OpenACCLoopConstruct &x,
       parser::Block &block, parser::Block::iterator it) {
-    // Check the sequence of DoConstruct in the same iteration
-    //
-    // Original:
-    //   ExecutableConstruct -> OpenACCConstruct -> OpenACCLoopConstruct
-    //     ACCBeginLoopDirective
-    //   ExecutableConstruct -> DoConstruct
-    //
-    // After rewriting:
-    //   ExecutableConstruct -> OpenACCConstruct -> OpenACCLoopConstruct
-    //     AccBeginLoopDirective
-    //     DoConstruct
-    parser::Block::iterator nextIt;
     auto &beginDir{std::get<parser::AccBeginLoopDirective>(x.t)};
     auto &dir{std::get<parser::AccLoopDirective>(beginDir.t)};
+    const auto &doCons{std::get<parser::DoConstruct>(x.t)};
 
-    nextIt = it;
-    if (++nextIt != block.end()) {
-      if (auto *doCons{parser::Unwrap<parser::DoConstruct>(*nextIt)}) {
-        if (!doCons->GetLoopControl()) {
-          messages_.Say(dir.source,
-              "DO loop after the %s directive must have loop control"_err_en_US,
-              parser::ToUpperCaseLetters(dir.source.ToString()));
-          return;
-        }
-
-        // move DoConstruct
-        std::get<std::optional<parser::DoConstruct>>(x.t) = std::move(*doCons);
-        nextIt = block.erase(nextIt);
-
-        CheckDoConcurrentClauseRestriction<parser::OpenACCLoopConstruct,
-            parser::AccBeginLoopDirective>(x);
-        CheckTileClauseRestriction<parser::OpenACCLoopConstruct,
-            parser::AccBeginLoopDirective>(x);
-
-        return; // found do-loop
-      }
+    if (!doCons.GetLoopControl()) {
+      messages_.Say(dir.source,
+          "DO loop after the %s directive must have loop control"_err_en_US,
+          parser::ToUpperCaseLetters(dir.source.ToString()));
+      return;
     }
-    messages_.Say(dir.source,
-        "A DO loop must follow the %s directive"_err_en_US,
-        parser::ToUpperCaseLetters(dir.source.ToString()));
+
+    CheckDoConcurrentClauseRestriction<parser::OpenACCLoopConstruct,
+        parser::AccBeginLoopDirective>(x, doCons);
+    CheckTileClauseRestriction<parser::OpenACCLoopConstruct,
+        parser::AccBeginLoopDirective>(x, doCons);
   }
 
   void RewriteOpenACCCombinedConstruct(parser::OpenACCCombinedConstruct &x,
       parser::Block &block, parser::Block::iterator it) {
-    // Check the sequence of DoConstruct in the same iteration
-    //
-    // Original:
-    //   ExecutableConstruct -> OpenACCConstruct -> OpenACCCombinedConstruct
-    //     ACCBeginCombinedDirective
-    //   ExecutableConstruct -> DoConstruct
-    //   ExecutableConstruct -> AccEndCombinedDirective (if available)
-    //
-    // After rewriting:
-    //   ExecutableConstruct -> OpenACCConstruct -> OpenACCCombinedConstruct
-    //     ACCBeginCombinedDirective
-    //     DoConstruct
-    //     AccEndCombinedDirective (if available)
+    // Check the sequence of DoConstruct in the same iteration.
     parser::Block::iterator nextIt;
     auto &beginDir{std::get<parser::AccBeginCombinedDirective>(x.t)};
     auto &dir{std::get<parser::AccCombinedDirective>(beginDir.t)};
-    auto &doConstruct{std::get<std::optional<parser::DoConstruct>>(x.t)};
+    const auto &doConstruct{std::get<std::optional<parser::DoConstruct>>(x.t)};
 
     if (doConstruct) {
       CheckDoConcurrentClauseRestriction<parser::OpenACCCombinedConstruct,
-          parser::AccBeginCombinedDirective>(x);
+          parser::AccBeginCombinedDirective>(x, *doConstruct);
       CheckTileClauseRestriction<parser::OpenACCCombinedConstruct,
-          parser::AccBeginCombinedDirective>(x);
+          parser::AccBeginCombinedDirective>(x, *doConstruct);
       if (!doConstruct->GetLoopControl()) {
         messages_.Say(dir.source,
             "DO loop after the %s directive must have loop control"_err_en_US,
diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -1088,8 +1088,8 @@
     return nullptr;
   };
 
-  const auto &outer{std::get<std::optional<parser::DoConstruct>>(x.t)};
-  for (const parser::DoConstruct *loop{&*outer}; loop && level > 0; --level) {
+  const auto &outer{std::get<parser::DoConstruct>(x.t)};
+  for (const parser::DoConstruct *loop{&outer}; loop && level > 0; --level) {
     // go through all the nested do-loops and resolve index variables
     const parser::Name *iv{GetLoopIndex(*loop)};
     if (iv) {
diff --git a/flang/test/Semantics/OpenACC/acc-canonicalization-validity.f90 b/flang/test/Semantics/OpenACC/acc-canonicalization-validity.f90
--- a/flang/test/Semantics/OpenACC/acc-canonicalization-validity.f90
+++ b/flang/test/Semantics/OpenACC/acc-canonicalization-validity.f90
@@ -15,9 +15,7 @@
   real(8) :: a(256)
   real(8) :: aa(256, 256)
 
-  !ERROR: A DO loop must follow the LOOP directive
-  !$acc loop
-  i = 1
+  i = 0
 
   !ERROR: DO loop after the LOOP directive must have loop control
   !$acc loop
diff --git a/flang/test/Semantics/OpenACC/acc-loop-validity.f90 b/flang/test/Semantics/OpenACC/acc-loop-validity.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Semantics/OpenACC/acc-loop-validity.f90
@@ -0,0 +1,15 @@
+! RUN: %python %S/../test_errors.py %s %flang -fopenacc
+
+program openacc_clause_validity
+
+  implicit none
+
+  integer :: i
+
+  i = 0
+
+  !$acc loop
+  !ERROR: A DO loop must follow the loop construct
+  i = 1
+
+end
diff --git a/flang/test/Semantics/OpenACC/acc-loop.f90 b/flang/test/Semantics/OpenACC/acc-loop.f90
--- a/flang/test/Semantics/OpenACC/acc-loop.f90
+++ b/flang/test/Semantics/OpenACC/acc-loop.f90
@@ -263,4 +263,9 @@
   do i = 1, N
   end do
 
+  !$acc loop
+  do i = 1, N
+  end do
+  !$acc end loop
+
 end program openacc_loop_validity