diff --git a/flang/include/flang/Parser/dump-parse-tree.h b/flang/include/flang/Parser/dump-parse-tree.h
index 0f10515c118c8..5318c34336a09 100644
--- a/flang/include/flang/Parser/dump-parse-tree.h
+++ b/flang/include/flang/Parser/dump-parse-tree.h
@@ -517,7 +517,6 @@ class ParseTreeDumper {
   NODE(OmpAppendArgsClause, OmpAppendOp)
   NODE(parser, OmpArgument)
   NODE(parser, OmpArgumentList)
-  NODE(parser, OmpAssumeDirective)
   NODE(parser, OmpAtClause)
   NODE_ENUM(OmpAtClause, ActionTime)
   NODE(parser, OmpAtomicDefaultMemOrderClause)
@@ -570,7 +569,6 @@ class ParseTreeDumper {
   NODE(parser, OmpDoacrossClause)
   NODE(parser, OmpDynGroupprivateClause)
   NODE(OmpDynGroupprivateClause, Modifier)
-  NODE(parser, OmpEndAssumeDirective)
   NODE(parser, OmpEndDirective)
   NODE(parser, OmpEndLoopDirective)
   NODE(parser, OmpEndSectionsDirective)
diff --git a/flang/include/flang/Parser/openmp-utils.h b/flang/include/flang/Parser/openmp-utils.h
index b4aa6f4d41b1c..3d3dfae290d96 100644
--- a/flang/include/flang/Parser/openmp-utils.h
+++ b/flang/include/flang/Parser/openmp-utils.h
@@ -38,7 +38,6 @@ struct ConstructId {
     static constexpr llvm::omp::Directive id{Id}; \
   }
 
-MAKE_CONSTR_ID(OmpAssumeDirective, D::OMPD_assume);
 MAKE_CONSTR_ID(OmpDeclareVariantDirective, D::OMPD_declare_variant);
 MAKE_CONSTR_ID(OmpErrorDirective, D::OMPD_error);
 MAKE_CONSTR_ID(OmpMetadirectiveDirective, D::OMPD_metadirective);
@@ -103,8 +102,7 @@ struct DirectiveNameScope {
     } else if constexpr (TupleTrait<T>) {
       if constexpr (std::is_base_of_v<OmpBlockConstruct, T>) {
         return std::get<OmpBeginDirective>(x.t).DirName();
-      } else if constexpr (std::is_same_v<T, OmpAssumeDirective> ||
-          std::is_same_v<T, OmpDeclareVariantDirective> ||
+      } else if constexpr (std::is_same_v<T, OmpDeclareVariantDirective> ||
           std::is_same_v<T, OmpErrorDirective> ||
           std::is_same_v<T, OmpMetadirectiveDirective> ||
           std::is_same_v<T, OpenMPDeclarativeAllocate> ||
diff --git a/flang/include/flang/Parser/parse-tree.h b/flang/include/flang/Parser/parse-tree.h
index e1e0d647f2fde..1d2361d1dd5ac 100644
--- a/flang/include/flang/Parser/parse-tree.h
+++ b/flang/include/flang/Parser/parse-tree.h
@@ -4835,28 +4835,14 @@ struct OpenMPDeclarativeAssumes {
   CharBlock source;
 };
 
-struct OmpAssumeDirective {
-  TUPLE_CLASS_BOILERPLATE(OmpAssumeDirective);
-  std::tuple<Verbatim, OmpClauseList> t;
-  CharBlock source;
-};
-
-struct OmpEndAssumeDirective {
-  WRAPPER_CLASS_BOILERPLATE(OmpEndAssumeDirective, Verbatim);
-  CharBlock source;
-};
-
-// Ref: [5.2: 213-216]
+// Ref: [5.1:86-89], [5.2:215], [6.0:369]
 //
-// assume-construct ->
-//   ASSUME absent-clause | contains-clause | holds_clause | no-openmp-clause
-//          no-openmp-routines-clause | no-parallelism-clause
-//       block
+// assume-directive ->                              // since 5.1
+//   ASSUME assumption-clause...
+//     block
 //   [END ASSUME]
-struct OpenMPAssumeConstruct {
-  TUPLE_CLASS_BOILERPLATE(OpenMPAssumeConstruct);
-  std::tuple<OmpAssumeDirective, Block, std::optional<OmpEndAssumeDirective>> t;
-  CharBlock source;
+struct OpenMPAssumeConstruct : public OmpBlockConstruct {
+  INHERITED_TUPLE_CLASS_BOILERPLATE(OpenMPAssumeConstruct, OmpBlockConstruct);
 };
 
 // 2.7.2 SECTIONS
diff --git a/flang/lib/Parser/openmp-parsers.cpp b/flang/lib/Parser/openmp-parsers.cpp
index 5c17ddff8d7d3..9d11b4c0da9f7 100644
--- a/flang/lib/Parser/openmp-parsers.cpp
+++ b/flang/lib/Parser/openmp-parsers.cpp
@@ -1857,16 +1857,8 @@ TYPE_PARSER(
                                 Parser<OmpMetadirectiveDirective>{})) /
                             endOmpLine))
 
-// Assume Construct
-TYPE_PARSER(sourced(construct<OmpAssumeDirective>(
-    verbatim("ASSUME"_tok), Parser<OmpClauseList>{})))
-
-TYPE_PARSER(sourced(construct<OmpEndAssumeDirective>(
-    startOmpLine >> verbatim("END ASSUME"_tok))))
-
-TYPE_PARSER(sourced(
-    construct<OpenMPAssumeConstruct>(Parser<OmpAssumeDirective>{} / endOmpLine,
-        block, maybe(Parser<OmpEndAssumeDirective>{} / endOmpLine))))
+TYPE_PARSER(construct<OpenMPAssumeConstruct>(
+    sourced(OmpBlockConstructParser{llvm::omp::Directive::OMPD_assume})))
 
 // Block Construct
 #define MakeBlockConstruct(dir) \
diff --git a/flang/lib/Parser/unparse.cpp b/flang/lib/Parser/unparse.cpp
index 1b5fdc3b2249e..d007a9e5acc55 100644
--- a/flang/lib/Parser/unparse.cpp
+++ b/flang/lib/Parser/unparse.cpp
@@ -2580,20 +2580,11 @@ class UnparseVisitor {
     Put("\n");
     EndOpenMP();
   }
-  void Unparse(const OpenMPAllocatorsConstruct &x) { //
+  void Unparse(const OpenMPAllocatorsConstruct &x) {
     Unparse(static_cast<const OmpBlockConstruct &>(x));
   }
-  void Unparse(const OmpAssumeDirective &x) {
-    BeginOpenMP();
-    Word("!$OMP ASSUME");
-    Walk(" ", std::get<OmpClauseList>(x.t).v);
-    Put("\n");
-    EndOpenMP();
-  }
-  void Unparse(const OmpEndAssumeDirective &x) {
-    BeginOpenMP();
-    Word("!$OMP END ASSUME\n");
-    EndOpenMP();
+  void Unparse(const OpenMPAssumeConstruct &x) {
+    Unparse(static_cast<const OmpBlockConstruct &>(x));
   }
   void Unparse(const OpenMPCriticalConstruct &x) {
     Unparse(static_cast<const OmpBlockConstruct &>(x));
diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
index 04f2ebcbcaee2..b94445e6d8547 100644
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -589,14 +589,6 @@ template <typename Checker> struct DirectiveSpellingVisitor {
     checker_(GetDirName(x.t).source, Directive::OMPD_allocators);
     return false;
   }
-  bool Pre(const parser::OmpAssumeDirective &x) {
-    checker_(std::get<parser::Verbatim>(x.t).source, Directive::OMPD_assume);
-    return false;
-  }
-  bool Pre(const parser::OmpEndAssumeDirective &x) {
-    checker_(x.v.source, Directive::OMPD_assume);
-    return false;
-  }
   bool Pre(const parser::OmpMetadirectiveDirective &x) {
     checker_(
         std::get<parser::Verbatim>(x.t).source, Directive::OMPD_metadirective);
diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index dbd4f512a0465..9c4d3a8738ee5 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -531,6 +531,9 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
   bool Pre(const parser::OpenMPDeclarativeAllocate &);
   void Post(const parser::OpenMPDeclarativeAllocate &) { PopContext(); }
 
+  bool Pre(const parser::OpenMPAssumeConstruct &);
+  void Post(const parser::OpenMPAssumeConstruct &) { PopContext(); }
+
   bool Pre(const parser::OpenMPAtomicConstruct &);
   void Post(const parser::OpenMPAtomicConstruct &) { PopContext(); }
 
@@ -2220,6 +2223,11 @@ bool OmpAttributeVisitor::Pre(const parser::OpenMPDeclarativeAllocate &x) {
   return false;
 }
 
+bool OmpAttributeVisitor::Pre(const parser::OpenMPAssumeConstruct &x) {
+  PushContext(x.source, llvm::omp::Directive::OMPD_assume);
+  return true;
+}
+
 bool OmpAttributeVisitor::Pre(const parser::OpenMPAtomicConstruct &x) {
   PushContext(x.source, llvm::omp::Directive::OMPD_atomic);
   return true;
diff --git a/flang/test/Parser/OpenMP/assumption.f90 b/flang/test/Parser/OpenMP/assumption.f90
index f1cb0c87e1262..0f333f99f9085 100644
--- a/flang/test/Parser/OpenMP/assumption.f90
+++ b/flang/test/Parser/OpenMP/assumption.f90
@@ -1,59 +1,149 @@
-! RUN: %flang_fc1  -fopenmp-version=51 -fopenmp -fdebug-unparse-no-sema %s 2>&1 | FileCheck %s
-! RUN: %flang_fc1  -fopenmp-version=51 -fopenmp -fdebug-dump-parse-tree-no-sema %s 2>&1 | FileCheck %s --check-prefix="PARSE-TREE"
+!RUN: %flang_fc1 -fopenmp-version=51 -fopenmp -fdebug-unparse-no-sema %s | FileCheck --check-prefix="UNPARSE" %s
+!RUN: %flang_fc1 -fopenmp-version=51 -fopenmp -fdebug-dump-parse-tree-no-sema %s | FileCheck --check-prefix="PARSE-TREE" %s
+
 subroutine sub1
   integer :: r
-!CHECK: !$OMP ASSUME NO_OPENMP
-!PARSE-TREE:   ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
-!PARSE-TREE:   Verbatim
-!PARSE-TREE:   OmpClauseList -> OmpClause -> NoOpenmp
   !$omp assume no_openmp
-!CHECK: !$OMP ASSUME NO_PARALLELISM
-!PARSE-TREE:   ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
-!PARSE-TREE:   Verbatim
-!PARSE-TREE:   OmpClauseList -> OmpClause -> NoParallelism
+  !$omp end assume
+
   !$omp assume no_parallelism
-!CHECK: !$OMP ASSUME NO_OPENMP_ROUTINES
-!PARSE-TREE:   ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
-!PARSE-TREE:   Verbatim
-!PARSE-TREE:   OmpClauseList -> OmpClause -> NoOpenmpRoutines  
+  !$omp end assume
+
   !$omp assume no_openmp_routines
-!CHECK: !$OMP ASSUME ABSENT(ALLOCATE), CONTAINS(WORKSHARE,TASK)
-!PARSE-TREE:   ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
-!PARSE-TREE:   Verbatim
-!PARSE-TREE:   OmpClauseList -> OmpClause -> Absent -> OmpAbsentClause -> llvm::omp::Directive = allocate
-!PARSE-TREE:   OmpClause -> Contains -> OmpContainsClause -> llvm::omp::Directive = workshare
-!PARSE-TREE:   llvm::omp::Directive = task
- !$omp assume absent(allocate), contains(workshare, task)
-!CHECK: !$OMP ASSUME HOLDS(1==1)
+  !$omp end assume
+
+  !$omp assume absent(allocate), contains(workshare, task)
+  block ! strictly-structured-block
+  end block
+
   !$omp assume holds(1.eq.1)
+  block
+  end block
   print *, r
 end subroutine sub1
 
+!UNPARSE: SUBROUTINE sub1
+!UNPARSE:  INTEGER r
+!UNPARSE: !$OMP ASSUME NO_OPENMP
+!UNPARSE: !$OMP END ASSUME
+!UNPARSE: !$OMP ASSUME NO_PARALLELISM
+!UNPARSE: !$OMP END ASSUME
+!UNPARSE: !$OMP ASSUME NO_OPENMP_ROUTINES
+!UNPARSE: !$OMP END ASSUME
+!UNPARSE: !$OMP ASSUME ABSENT(ALLOCATE) CONTAINS(WORKSHARE,TASK)
+!UNPARSE:  BLOCK
+!UNPARSE:  END BLOCK
+!UNPARSE: !$OMP ASSUME HOLDS(1==1)
+!UNPARSE:  BLOCK
+!UNPARSE:  END BLOCK
+!UNPARSE:  PRINT *, r
+!UNPARSE: END SUBROUTINE sub1
+
+!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
+!PARSE-TREE: | OmpBeginDirective
+!PARSE-TREE: | | OmpDirectiveName -> llvm::omp::Directive = assume
+!PARSE-TREE: | | OmpClauseList -> OmpClause -> NoOpenmp
+!PARSE-TREE: | | Flags = None
+!PARSE-TREE: | Block
+!PARSE-TREE: | OmpEndDirective
+!PARSE-TREE: | | OmpDirectiveName -> llvm::omp::Directive = assume
+!PARSE-TREE: | | OmpClauseList ->
+!PARSE-TREE: | | Flags = None
+!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
+!PARSE-TREE: | OmpBeginDirective
+!PARSE-TREE: | | OmpDirectiveName -> llvm::omp::Directive = assume
+!PARSE-TREE: | | OmpClauseList -> OmpClause -> NoParallelism
+!PARSE-TREE: | | Flags = None
+!PARSE-TREE: | Block
+!PARSE-TREE: | OmpEndDirective
+!PARSE-TREE: | | OmpDirectiveName -> llvm::omp::Directive = assume
+!PARSE-TREE: | | OmpClauseList ->
+!PARSE-TREE: | | Flags = None
+!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
+!PARSE-TREE: | OmpBeginDirective
+!PARSE-TREE: | | OmpDirectiveName -> llvm::omp::Directive = assume
+!PARSE-TREE: | | OmpClauseList -> OmpClause -> NoOpenmpRoutines
+!PARSE-TREE: | | Flags = None
+!PARSE-TREE: | Block
+!PARSE-TREE: | OmpEndDirective
+!PARSE-TREE: | | OmpDirectiveName -> llvm::omp::Directive = assume
+!PARSE-TREE: | | OmpClauseList ->
+!PARSE-TREE: | | Flags = None
+!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
+!PARSE-TREE: | OmpBeginDirective
+!PARSE-TREE: | | OmpDirectiveName -> llvm::omp::Directive = assume
+!PARSE-TREE: | | OmpClauseList -> OmpClause -> Absent -> OmpAbsentClause -> llvm::omp::Directive = allocate
+!PARSE-TREE: | | OmpClause -> Contains -> OmpContainsClause -> llvm::omp::Directive = workshare
+!PARSE-TREE: | | llvm::omp::Directive = task
+!PARSE-TREE: | | Flags = None
+!PARSE-TREE: | Block
+!PARSE-TREE: | | ExecutionPartConstruct -> ExecutableConstruct -> BlockConstruct
+!PARSE-TREE: | | | BlockStmt ->
+!PARSE-TREE: | | | BlockSpecificationPart -> SpecificationPart
+!PARSE-TREE: | | | | ImplicitPart ->
+!PARSE-TREE: | | | Block
+!PARSE-TREE: | | | EndBlockStmt ->
+!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
+!PARSE-TREE: | OmpBeginDirective
+!PARSE-TREE: | | OmpDirectiveName -> llvm::omp::Directive = assume
+!PARSE-TREE: | | OmpClauseList -> OmpClause -> Holds -> OmpHoldsClause -> Expr -> EQ
+!PARSE-TREE: | | | Expr -> LiteralConstant -> IntLiteralConstant = '1'
+!PARSE-TREE: | | | Expr -> LiteralConstant -> IntLiteralConstant = '1'
+!PARSE-TREE: | | Flags = None
+!PARSE-TREE: | Block
+!PARSE-TREE: | | ExecutionPartConstruct -> ExecutableConstruct -> BlockConstruct
+!PARSE-TREE: | | | BlockStmt ->
+!PARSE-TREE: | | | BlockSpecificationPart -> SpecificationPart
+!PARSE-TREE: | | | | ImplicitPart ->
+!PARSE-TREE: | | | Block
+!PARSE-TREE: | | | EndBlockStmt ->
+
+
 subroutine sub2
   integer :: r
   integer :: v
-!CHECK !$OMP ASSUME NO_OPENMP
-!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
-!PARSE-TREE: OmpAssumeDirective
-!PARSE-TREE: Verbatim
-!PARSE-TREE: OmpClauseList -> OmpClause -> NoOpenmp
-!PARSE-TREE: Block
-!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> ActionStmt -> AssignmentStmt
-!PARSE-TREE: Expr -> Add
-!PARSE-TREE: OmpEndAssumeDirective
   v = 87
   !$omp assume no_openmp
   r = r + 1
-!CHECK !$OMP END ASSUME
   !$omp end assume
 end subroutine sub2
-  
+
+!UNPARSE: SUBROUTINE sub2
+!UNPARSE:  INTEGER r
+!UNPARSE:  INTEGER v
+!UNPARSE:  v = 87
+!UNPARSE: !$OMP ASSUME NO_OPENMP
+!UNPARSE:  r = r+1
+!UNPARSE: !$OMP END ASSUME
+!UNPARSE: END SUBROUTINE sub2
+
+!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> ActionStmt -> AssignmentStmt
+!PARSE-TREE: | Variable -> Designator -> DataRef -> Name = 'v'
+!PARSE-TREE: | Expr -> LiteralConstant -> IntLiteralConstant = '87'
+!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPAssumeConstruct
+!PARSE-TREE: | OmpBeginDirective
+!PARSE-TREE: | | OmpDirectiveName -> llvm::omp::Directive = assume
+!PARSE-TREE: | | OmpClauseList -> OmpClause -> NoOpenmp
+!PARSE-TREE: | | Flags = None
+!PARSE-TREE: | Block
+!PARSE-TREE: | | ExecutionPartConstruct -> ExecutableConstruct -> ActionStmt -> AssignmentStmt
+!PARSE-TREE: | | | Variable -> Designator -> DataRef -> Name = 'r'
+!PARSE-TREE: | | | Expr -> Add
+!PARSE-TREE: | | | | Expr -> Designator -> DataRef -> Name = 'r'
+!PARSE-TREE: | | | | Expr -> LiteralConstant -> IntLiteralConstant = '1'
+!PARSE-TREE: | OmpEndDirective
+!PARSE-TREE: | | OmpDirectiveName -> llvm::omp::Directive = assume
+!PARSE-TREE: | | OmpClauseList ->
+!PARSE-TREE: | | Flags = None
+
 program p
-!CHECK !$OMP ASSUMES NO_OPENMP
-!PARSE-TREE: SpecificationPart
-!PARSE-TREE:   OpenMPDeclarativeConstruct -> OpenMPDeclarativeAssumes
-!PARSE-TREE: Verbatim
-!PARSE-TREE: OmpClauseList -> OmpClause -> NoOpenmp
   !$omp assumes no_openmp
 end program p
-  
+
+!UNPARSE: PROGRAM p
+!UNPARSE: !$OMP ASSUMES  NO_OPENMP
+!UNPARSE: END PROGRAM p
+
+!PARSE-TREE: OpenMPDeclarativeConstruct -> OpenMPDeclarativeAssumes
+!PARSE-TREE: | Verbatim
+!PARSE-TREE: | OmpClauseList -> OmpClause -> NoOpenmp