diff --git a/flang/include/flang/Parser/dump-parse-tree.h b/flang/include/flang/Parser/dump-parse-tree.h
index 040065c0cbc02..76d2f164fc4bf 100644
--- a/flang/include/flang/Parser/dump-parse-tree.h
+++ b/flang/include/flang/Parser/dump-parse-tree.h
@@ -476,6 +476,7 @@ class ParseTreeDumper {
   NODE(parser, OldParameterStmt)
   NODE(parser, OmpIteratorSpecifier)
   NODE(parser, OmpIteratorModifier)
+  NODE(parser, OmpAffinityClause)
   NODE(parser, OmpAlignedClause)
   NODE(parser, OmpAtomic)
   NODE(parser, OmpAtomicCapture)
diff --git a/flang/include/flang/Parser/parse-tree.h b/flang/include/flang/Parser/parse-tree.h
index f727525a759e6..c1884f6e88d1e 100644
--- a/flang/include/flang/Parser/parse-tree.h
+++ b/flang/include/flang/Parser/parse-tree.h
@@ -3458,6 +3458,13 @@ struct OmpReductionOperator {
 
 // --- Clauses
 
+// OMP 5.0 2.10.1 affinity([aff-modifier:] locator-list)
+//                aff-modifier: interator-modifier
+struct OmpAffinityClause {
+  TUPLE_CLASS_BOILERPLATE(OmpAffinityClause);
+  std::tuple<std::optional<OmpIteratorModifier>, OmpObjectList> t;
+};
+
 // 2.8.1 aligned-clause -> ALIGNED (variable-name-list[ : scalar-constant])
 struct OmpAlignedClause {
   TUPLE_CLASS_BOILERPLATE(OmpAlignedClause);
diff --git a/flang/lib/Lower/OpenMP/Clauses.cpp b/flang/lib/Lower/OpenMP/Clauses.cpp
index 8974b4211b968..ee3d74a7c631a 100644
--- a/flang/lib/Lower/OpenMP/Clauses.cpp
+++ b/flang/lib/Lower/OpenMP/Clauses.cpp
@@ -352,8 +352,15 @@ Absent make(const parser::OmpClause::Absent &inp,
 
 Affinity make(const parser::OmpClause::Affinity &inp,
               semantics::SemanticsContext &semaCtx) {
-  // inp -> empty
-  llvm_unreachable("Empty: affinity");
+  // inp.v -> parser::OmpAffinityClause
+  auto &t0 = std::get<std::optional<parser::OmpIteratorModifier>>(inp.v.t);
+  auto &t1 = std::get<parser::OmpObjectList>(inp.v.t);
+
+  auto &&maybeIter =
+      maybeApply([&](auto &&s) { return makeIterator(s, semaCtx); }, t0);
+
+  return Affinity{{/*Iterator=*/std::move(maybeIter),
+                   /*LocatorList=*/makeObjects(t1, semaCtx)}};
 }
 
 Align make(const parser::OmpClause::Align &inp,
diff --git a/flang/lib/Lower/OpenMP/OpenMP.cpp b/flang/lib/Lower/OpenMP/OpenMP.cpp
index 52a077cd5a797..fc54da8babe63 100644
--- a/flang/lib/Lower/OpenMP/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP/OpenMP.cpp
@@ -2769,7 +2769,8 @@ static void genOMP(lower::AbstractConverter &converter, lower::SymMap &symTable,
 
   for (const Clause &clause : clauses) {
     mlir::Location clauseLocation = converter.genLocation(clause.source);
-    if (!std::holds_alternative<clause::Allocate>(clause.u) &&
+    if (!std::holds_alternative<clause::Affinity>(clause.u) &&
+        !std::holds_alternative<clause::Allocate>(clause.u) &&
         !std::holds_alternative<clause::Copyin>(clause.u) &&
         !std::holds_alternative<clause::Copyprivate>(clause.u) &&
         !std::holds_alternative<clause::Default>(clause.u) &&
diff --git a/flang/lib/Parser/openmp-parsers.cpp b/flang/lib/Parser/openmp-parsers.cpp
index 4a1daed04f3e9..59a8757e58e8c 100644
--- a/flang/lib/Parser/openmp-parsers.cpp
+++ b/flang/lib/Parser/openmp-parsers.cpp
@@ -177,6 +177,11 @@ TYPE_PARSER(construct<OmpIteratorSpecifier>(
 TYPE_PARSER(construct<OmpIteratorModifier>("ITERATOR" >>
     parenthesized(nonemptyList(sourced(Parser<OmpIteratorSpecifier>{})))))
 
+// [5.0] 2.10.1 affinity([aff-modifier:] locator-list)
+//              aff-modifier: interator-modifier
+TYPE_PARSER(construct<OmpAffinityClause>(
+    maybe(Parser<OmpIteratorModifier>{} / ":"), Parser<OmpObjectList>{}))
+
 // 2.15.3.1 DEFAULT (PRIVATE | FIRSTPRIVATE | SHARED | NONE)
 TYPE_PARSER(construct<OmpDefaultClause>(
     "PRIVATE" >> pure(OmpDefaultClause::Type::Private) ||
@@ -415,6 +420,8 @@ TYPE_PARSER(construct<OmpLastprivateClause>(
 TYPE_PARSER(
     "ACQUIRE" >> construct<OmpClause>(construct<OmpClause::Acquire>()) ||
     "ACQ_REL" >> construct<OmpClause>(construct<OmpClause::AcqRel>()) ||
+    "AFFINITY" >> construct<OmpClause>(construct<OmpClause::Affinity>(
+                      parenthesized(Parser<OmpAffinityClause>{}))) ||
     "ALIGNED" >> construct<OmpClause>(construct<OmpClause::Aligned>(
                      parenthesized(Parser<OmpAlignedClause>{}))) ||
     "ALLOCATE" >> construct<OmpClause>(construct<OmpClause::Allocate>(
diff --git a/flang/lib/Parser/unparse.cpp b/flang/lib/Parser/unparse.cpp
index 5870aba0132c8..04df988223e8f 100644
--- a/flang/lib/Parser/unparse.cpp
+++ b/flang/lib/Parser/unparse.cpp
@@ -2129,6 +2129,10 @@ class UnparseVisitor {
     Walk(std::get<std::optional<OmpDeviceClause::DeviceModifier>>(x.t), ":");
     Walk(std::get<ScalarIntExpr>(x.t));
   }
+  void Unparse(const OmpAffinityClause &x) {
+    Walk(std::get<std::optional<OmpIteratorModifier>>(x.t), ":");
+    Walk(std::get<OmpObjectList>(x.t));
+  }
   void Unparse(const OmpAlignedClause &x) {
     Walk(std::get<OmpObjectList>(x.t));
     Put(",");
diff --git a/flang/test/Lower/OpenMP/Todo/affinity-clause.f90 b/flang/test/Lower/OpenMP/Todo/affinity-clause.f90
new file mode 100644
index 0000000000000..3459dd219e425
--- /dev/null
+++ b/flang/test/Lower/OpenMP/Todo/affinity-clause.f90
@@ -0,0 +1,10 @@
+!RUN: %not_todo_cmd bbc -emit-hlfir -fopenmp -fopenmp-version=50 -o - %s 2>&1 | FileCheck %s
+!RUN: %not_todo_cmd %flang_fc1 -emit-hlfir -fopenmp -fopenmp-version=50 -o - %s 2>&1 | FileCheck %s
+
+!CHECK: not yet implemented: Unhandled clause AFFINITY in TASK construct
+subroutine f00(x)
+  integer :: x(10)
+!$omp task affinity(x)
+  x = x + 1
+!$omp end task
+end
diff --git a/flang/test/Parser/OpenMP/affinity-clause.f90 b/flang/test/Parser/OpenMP/affinity-clause.f90
new file mode 100644
index 0000000000000..804723cad7b2b
--- /dev/null
+++ b/flang/test/Parser/OpenMP/affinity-clause.f90
@@ -0,0 +1,79 @@
+!RUN: %flang_fc1 -fdebug-unparse -fopenmp -fopenmp-version=50 %s | FileCheck --ignore-case --check-prefix="UNPARSE" %s
+!RUN: %flang_fc1 -fdebug-dump-parse-tree -fopenmp -fopenmp-version=50 %s | FileCheck --check-prefix="PARSE-TREE" %s
+
+subroutine f00(x)
+  integer :: x(10)
+!$omp task affinity(x)
+  x = x + 1
+!$omp end task
+end
+
+!UNPARSE: SUBROUTINE f00 (x)
+!UNPARSE:  INTEGER x(10_4)
+!UNPARSE: !$OMP TASK  AFFINITY(x)
+!UNPARSE:   x=x+1_4
+!UNPARSE: !$OMP END TASK
+!UNPARSE: END SUBROUTINE
+
+!PARSE-TREE: OmpBeginBlockDirective
+!PARSE-TREE: | OmpBlockDirective -> llvm::omp::Directive = task
+!PARSE-TREE: | OmpClauseList -> OmpClause -> Affinity -> OmpAffinityClause
+!PARSE-TREE: | | OmpObjectList -> OmpObject -> Designator -> DataRef -> Name = 'x'
+
+subroutine f01(x)
+  integer :: x(10)
+!$omp task affinity(x(1), x(3))
+  x = x + 1
+!$omp end task
+end
+
+!UNPARSE: SUBROUTINE f01 (x)
+!UNPARSE:  INTEGER x(10_4)
+!UNPARSE: !$OMP TASK  AFFINITY(x(1_4),x(3_4))
+!UNPARSE:   x=x+1_4
+!UNPARSE: !$OMP END TASK
+!UNPARSE: END SUBROUTINE
+
+!PARSE-TREE: OmpBeginBlockDirective
+!PARSE-TREE: | OmpBlockDirective -> llvm::omp::Directive = task
+!PARSE-TREE: | OmpClauseList -> OmpClause -> Affinity -> OmpAffinityClause
+!PARSE-TREE: | | OmpObjectList -> OmpObject -> Designator -> DataRef -> ArrayElement
+!PARSE-TREE: | | | DataRef -> Name = 'x'
+!PARSE-TREE: | | | SectionSubscript -> Integer -> Expr = '1_4'
+!PARSE-TREE: | | | | LiteralConstant -> IntLiteralConstant = '1'
+!PARSE-TREE: | | OmpObject -> Designator -> DataRef -> ArrayElement
+!PARSE-TREE: | | | DataRef -> Name = 'x'
+!PARSE-TREE: | | | SectionSubscript -> Integer -> Expr = '3_4'
+!PARSE-TREE: | | | | LiteralConstant -> IntLiteralConstant = '3'
+
+subroutine f02(x)
+  integer :: x(10)
+!$omp task affinity(iterator(i = 1:3): x(i))
+  x = x + 1
+!$omp end task
+end
+
+!UNPARSE: SUBROUTINE f02 (x)
+!UNPARSE:  INTEGER x(10_4)
+!UNPARSE: !$OMP TASK  AFFINITY(ITERATOR(INTEGER i = 1_4:3_4):x(i))
+!UNPARSE:   x=x+1_4
+!UNPARSE: !$OMP END TASK
+!UNPARSE: END SUBROUTINE
+
+!PARSE-TREE: OmpBeginBlockDirective
+!PARSE-TREE: | OmpBlockDirective -> llvm::omp::Directive = task
+!PARSE-TREE: | OmpClauseList -> OmpClause -> Affinity -> OmpAffinityClause
+!PARSE-TREE: | | OmpIteratorModifier -> OmpIteratorSpecifier
+!PARSE-TREE: | | | TypeDeclarationStmt
+!PARSE-TREE: | | | | DeclarationTypeSpec -> IntrinsicTypeSpec -> IntegerTypeSpec ->
+!PARSE-TREE: | | | | EntityDecl
+!PARSE-TREE: | | | | | Name = 'i'
+!PARSE-TREE: | | | SubscriptTriplet
+!PARSE-TREE: | | | | Scalar -> Integer -> Expr = '1_4'
+!PARSE-TREE: | | | | | LiteralConstant -> IntLiteralConstant = '1'
+!PARSE-TREE: | | | | Scalar -> Integer -> Expr = '3_4'
+!PARSE-TREE: | | | | | LiteralConstant -> IntLiteralConstant = '3'
+!PARSE-TREE: | | OmpObjectList -> OmpObject -> Designator -> DataRef -> ArrayElement
+!PARSE-TREE: | | | DataRef -> Name = 'x'
+!PARSE-TREE: | | | SectionSubscript -> Integer -> Expr = 'i'
+!PARSE-TREE: | | | | Designator -> DataRef -> Name = 'i'
diff --git a/flang/test/Semantics/OpenMP/affinity-clause.f90 b/flang/test/Semantics/OpenMP/affinity-clause.f90
new file mode 100644
index 0000000000000..53b2c4fc56677
--- /dev/null
+++ b/flang/test/Semantics/OpenMP/affinity-clause.f90
@@ -0,0 +1,9 @@
+!RUN: %python %S/../test_errors.py %s %flang -fopenmp -fopenmp-version=45
+
+subroutine f00(x)
+  integer :: x(10)
+!ERROR: AFFINITY clause is not allowed on directive TASK in OpenMP v4.5, try -fopenmp-version=50
+!$omp task affinity(x)
+  x = x + 1
+!$omp end task
+end
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMP.td b/llvm/include/llvm/Frontend/OpenMP/OMP.td
index f784c37cbe955..1834ad4d037f3 100644
--- a/llvm/include/llvm/Frontend/OpenMP/OMP.td
+++ b/llvm/include/llvm/Frontend/OpenMP/OMP.td
@@ -45,6 +45,7 @@ def OMPC_AdjustArgs : Clause<"adjust_args"> {
 }
 def OMPC_Affinity : Clause<"affinity"> {
   let clangClass = "OMPAffinityClause";
+  let flangClass = "OmpAffinityClause";
 }
 def OMPC_Align : Clause<"align"> {
   let clangClass = "OMPAlignClause";