diff --git a/flang/include/flang/Optimizer/Builder/Runtime/Numeric.h b/flang/include/flang/Optimizer/Builder/Runtime/Numeric.h
--- a/flang/include/flang/Optimizer/Builder/Runtime/Numeric.h
+++ b/flang/include/flang/Optimizer/Builder/Runtime/Numeric.h
@@ -38,6 +38,10 @@
 mlir::Value genScale(fir::FirOpBuilder &builder, mlir::Location loc,
                      mlir::Value x, mlir::Value i);
 
+/// Generate call to Selected_int_kind intrinsic runtime routine.
+mlir::Value genSelectedIntKind(fir::FirOpBuilder &builder, mlir::Location loc,
+                               mlir::Value x);
+
 /// Generate call to Selected_real_kind intrinsic runtime routine.
 mlir::Value genSelectedRealKind(fir::FirOpBuilder &builder, mlir::Location loc,
                                 mlir::Value precision, mlir::Value range,
diff --git a/flang/include/flang/Runtime/numeric.h b/flang/include/flang/Runtime/numeric.h
--- a/flang/include/flang/Runtime/numeric.h
+++ b/flang/include/flang/Runtime/numeric.h
@@ -355,6 +355,10 @@
     CppTypeFor<TypeCategory::Real, 16>, std::int64_t);
 #endif
 
+// SELECTED_INT_KIND
+CppTypeFor<TypeCategory::Integer, 4> RTNAME(SelectedIntKind)(
+    const char *, int, void *, int);
+
 // SELECTED_REAL_KIND
 CppTypeFor<TypeCategory::Integer, 4> RTNAME(SelectedRealKind)(
     const char *, int, void *, int, void *, int, void *, int);
diff --git a/flang/lib/Lower/IntrinsicCall.cpp b/flang/lib/Lower/IntrinsicCall.cpp
--- a/flang/lib/Lower/IntrinsicCall.cpp
+++ b/flang/lib/Lower/IntrinsicCall.cpp
@@ -545,6 +545,7 @@
                            llvm::ArrayRef<mlir::Value> args);
   mlir::Value genScale(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue genScan(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
+  mlir::Value genSelectedIntKind(mlir::Type, llvm::ArrayRef<mlir::Value>);
   mlir::Value genSelectedRealKind(mlir::Type, llvm::ArrayRef<mlir::Value>);
   mlir::Value genSetExponent(mlir::Type resultType,
                              llvm::ArrayRef<mlir::Value> args);
@@ -920,6 +921,10 @@
        {"back", asValue, handleDynamicOptional},
        {"kind", asValue}}},
      /*isElemental=*/true},
+    {"selected_int_kind",
+     &I::genSelectedIntKind,
+     {{{"scalar", asAddr}}},
+     /*isElemental=*/false},
     {"selected_real_kind",
      &I::genSelectedRealKind,
      {{{"precision", asAddr, handleDynamicOptional},
@@ -3768,6 +3773,17 @@
 
 // SELECTED_INT_KIND
 mlir::Value
+IntrinsicLibrary::genSelectedIntKind(mlir::Type resultType,
+                                     llvm::ArrayRef<mlir::Value> args) {
+  assert(args.size() == 1);
+
+  return builder.createConvert(
+      loc, resultType,
+      fir::runtime::genSelectedIntKind(builder, loc, fir::getBase(args[0])));
+}
+
+// SELECTED_REAL_KIND
+mlir::Value
 IntrinsicLibrary::genSelectedRealKind(mlir::Type resultType,
                                       llvm::ArrayRef<mlir::Value> args) {
   assert(args.size() == 3);
diff --git a/flang/lib/Optimizer/Builder/Runtime/Numeric.cpp b/flang/lib/Optimizer/Builder/Runtime/Numeric.cpp
--- a/flang/lib/Optimizer/Builder/Runtime/Numeric.cpp
+++ b/flang/lib/Optimizer/Builder/Runtime/Numeric.cpp
@@ -360,6 +360,27 @@
   return builder.create<fir::CallOp>(loc, func, args).getResult(0);
 }
 
+/// Generate call to Selected_int_kind intrinsic runtime routine.
+mlir::Value fir::runtime::genSelectedIntKind(fir::FirOpBuilder &builder,
+                                             mlir::Location loc,
+                                             mlir::Value x) {
+  mlir::func::FuncOp func =
+      fir::runtime::getRuntimeFunc<mkRTKey(SelectedIntKind)>(loc, builder);
+  auto fTy = func.getFunctionType();
+  auto sourceFile = fir::factory::locationToFilename(builder, loc);
+  auto sourceLine =
+      fir::factory::locationToLineNo(builder, loc, fTy.getInput(1));
+  if (!fir::isa_ref_type(x.getType()))
+    fir::emitFatalError(loc, "argument address for runtime not found");
+  mlir::Type eleTy = fir::unwrapRefType(x.getType());
+  mlir::Value xKind = builder.createIntegerConstant(
+      loc, fTy.getInput(3), eleTy.getIntOrFloatBitWidth() / 8);
+  auto args = fir::runtime::createArguments(builder, loc, fTy, sourceFile,
+                                            sourceLine, x, xKind);
+
+  return builder.create<fir::CallOp>(loc, func, args).getResult(0);
+}
+
 /// Generate call to Selected_real_kind intrinsic runtime routine.
 mlir::Value fir::runtime::genSelectedRealKind(fir::FirOpBuilder &builder,
                                               mlir::Location loc,
diff --git a/flang/runtime/numeric.cpp b/flang/runtime/numeric.cpp
--- a/flang/runtime/numeric.cpp
+++ b/flang/runtime/numeric.cpp
@@ -142,6 +142,25 @@
   return std::ldexp(x, p); // x*2**p
 }
 
+// SELECTED_INT_KIND (16.9.169)
+template <typename T>
+inline CppTypeFor<TypeCategory::Integer, 4> SelectedIntKind(T x) {
+  if (x <= 2) {
+    return 1;
+  } else if (x <= 4) {
+    return 2;
+  } else if (x <= 9) {
+    return 4;
+  } else if (x <= 18) {
+    return 8;
+#ifdef __SIZEOF_INT128__
+  } else if (x <= 38) {
+    return 16;
+#endif
+  }
+  return -1;
+}
+
 // SELECTED_REAL_KIND (16.9.170)
 template <typename P, typename R, typename D>
 inline CppTypeFor<TypeCategory::Integer, 4> SelectedRealKind(P p, R r, D d) {
@@ -794,6 +813,20 @@
 }
 #endif
 
+// SELECTED_INT_KIND
+CppTypeFor<TypeCategory::Integer, 4> RTNAME(SelectedIntKind)(
+    const char *source, int line, void *x, int xKind) {
+#ifdef __SIZEOF_INT128__
+  CppTypeFor<TypeCategory::Integer, 16> r =
+      getIntArgValue<CppTypeFor<TypeCategory::Integer, 16>>(
+          source, line, x, xKind, /*defaultValue*/ 0, /*resKind*/ 16);
+#else
+  std::int64_t r = getIntArgValue<std::int64_t>(
+      source, line, x, xKind, /*defaultValue*/ 0, /*resKind*/ 8);
+#endif
+  return SelectedIntKind(r);
+}
+
 // SELECTED_REAL_KIND
 CppTypeFor<TypeCategory::Integer, 4> RTNAME(SelectedRealKind)(
     const char *source, int line, void *precision, int pKind, void *range,
diff --git a/flang/test/Lower/Intrinsics/selected_int_kind.f90 b/flang/test/Lower/Intrinsics/selected_int_kind.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Lower/Intrinsics/selected_int_kind.f90
@@ -0,0 +1,81 @@
+! REQUIRES: shell
+! RUN: bbc -emit-fir %s -o - | FileCheck %s
+
+! CHECK-LABEL: func.func @_QPselected_int_kind_test1(
+! CHECK-SAME:                                        %[[VAL_0:.*]]: !fir.ref<i8> {fir.bindc_name = "a"}) {
+! CHECK:         %[[VAL_1:.*]] = fir.alloca i8 {bindc_name = "res", uniq_name = "_QFselected_int_kind_test1Eres"}
+! CHECK:         %[[VAL_4:.*]] = arith.constant 1 : i32
+! CHECK:         %[[VAL_6:.*]] = fir.convert %[[VAL_0]] : (!fir.ref<i8>) -> !fir.llvm_ptr<i8>
+! CHECK:         %[[VAL_7:.*]] = fir.call @_FortranASelectedIntKind(%{{.*}}, %{{.*}}, %[[VAL_6]], %[[VAL_4]]) : (!fir.ref<i8>, i32, !fir.llvm_ptr<i8>, i32) -> i32
+! CHECK:         %[[VAL_8:.*]] = fir.convert %[[VAL_7]] : (i32) -> i8
+! CHECK:         fir.store %[[VAL_8]] to %[[VAL_1]] : !fir.ref<i8>
+! CHECK:         return
+! CHECK:       }
+
+subroutine selected_int_kind_test1(a)
+  integer(1) :: a, res
+  res = selected_int_kind(a)
+end
+
+! CHECK-LABEL: func.func @_QPselected_int_kind_test2(
+! CHECK-SAME:                                        %[[VAL_0:.*]]: !fir.ref<i16> {fir.bindc_name = "a"}) {
+! CHECK:         %[[VAL_1:.*]] = fir.alloca i16 {bindc_name = "res", uniq_name = "_QFselected_int_kind_test2Eres"}
+! CHECK:         %[[VAL_4:.*]] = arith.constant 2 : i32
+! CHECK:         %[[VAL_6:.*]] = fir.convert %[[VAL_0]] : (!fir.ref<i16>) -> !fir.llvm_ptr<i8>
+! CHECK:         %[[VAL_7:.*]] = fir.call @_FortranASelectedIntKind(%{{.*}}, %{{.*}}, %[[VAL_6]], %[[VAL_4]]) : (!fir.ref<i8>, i32, !fir.llvm_ptr<i8>, i32) -> i32
+! CHECK:         %[[VAL_8:.*]] = fir.convert %[[VAL_7]] : (i32) -> i16
+! CHECK:         fir.store %[[VAL_8]] to %[[VAL_1]] : !fir.ref<i16>
+! CHECK:         return
+! CHECK:       }
+
+subroutine selected_int_kind_test2(a)
+  integer(2) :: a, res
+  res = selected_int_kind(a)
+end
+
+! CHECK-LABEL: func.func @_QPselected_int_kind_test4(
+! CHECK-SAME:                                        %[[VAL_0:.*]]: !fir.ref<i32> {fir.bindc_name = "a"}) {
+! CHECK:         %[[VAL_1:.*]] = fir.alloca i32 {bindc_name = "res", uniq_name = "_QFselected_int_kind_test4Eres"}
+! CHECK:         %[[VAL_4:.*]] = arith.constant 4 : i32
+! CHECK:         %[[VAL_6:.*]] = fir.convert %[[VAL_0]] : (!fir.ref<i32>) -> !fir.llvm_ptr<i8>
+! CHECK:         %[[VAL_7:.*]] = fir.call @_FortranASelectedIntKind(%{{.*}}, %{{.*}}, %[[VAL_6]], %[[VAL_4]]) : (!fir.ref<i8>, i32, !fir.llvm_ptr<i8>, i32) -> i32
+! CHECK:         fir.store %[[VAL_7]] to %[[VAL_1]] : !fir.ref<i32>
+! CHECK:         return
+! CHECK:       }
+
+subroutine selected_int_kind_test4(a)
+  integer(4) :: a, res
+  res = selected_int_kind(a)
+end
+
+! CHECK-LABEL: func.func @_QPselected_int_kind_test8(
+! CHECK-SAME:                                        %[[VAL_0:.*]]: !fir.ref<i64> {fir.bindc_name = "a"}) {
+! CHECK:         %[[VAL_1:.*]] = fir.alloca i64 {bindc_name = "res", uniq_name = "_QFselected_int_kind_test8Eres"}
+! CHECK:         %[[VAL_4:.*]] = arith.constant 8 : i32
+! CHECK:         %[[VAL_6:.*]] = fir.convert %[[VAL_0]] : (!fir.ref<i64>) -> !fir.llvm_ptr<i8>
+! CHECK:         %[[VAL_7:.*]] = fir.call @_FortranASelectedIntKind(%{{.*}}, %{{.*}}, %[[VAL_6]], %[[VAL_4]]) : (!fir.ref<i8>, i32, !fir.llvm_ptr<i8>, i32) -> i32
+! CHECK:         %[[VAL_8:.*]] = fir.convert %[[VAL_7]] : (i32) -> i64
+! CHECK:         fir.store %[[VAL_8]] to %[[VAL_1]] : !fir.ref<i64>
+! CHECK:         return
+! CHECK:       }
+
+subroutine selected_int_kind_test8(a)
+  integer(8) :: a, res
+  res = selected_int_kind(a)
+end
+
+! CHECK-LABEL: func.func @_QPselected_int_kind_test16(
+! CHECK-SAME:                                         %[[VAL_0:.*]]: !fir.ref<i128> {fir.bindc_name = "a"}) {
+! CHECK:         %[[VAL_1:.*]] = fir.alloca i128 {bindc_name = "res", uniq_name = "_QFselected_int_kind_test16Eres"}
+! CHECK:         %[[VAL_4:.*]] = arith.constant 16 : i32
+! CHECK:         %[[VAL_6:.*]] = fir.convert %[[VAL_0]] : (!fir.ref<i128>) -> !fir.llvm_ptr<i8>
+! CHECK:         %[[VAL_7:.*]] = fir.call @_FortranASelectedIntKind(%{{.*}}, %{{.*}}, %[[VAL_6]], %[[VAL_4]]) : (!fir.ref<i8>, i32, !fir.llvm_ptr<i8>, i32) -> i32
+! CHECK:         %[[VAL_8:.*]] = fir.convert %[[VAL_7]] : (i32) -> i128
+! CHECK:         fir.store %[[VAL_8]] to %[[VAL_1]] : !fir.ref<i128>
+! CHECK:         return
+! CHECK:       }
+
+subroutine selected_int_kind_test16(a)
+  integer(16) :: a, res
+  res = selected_int_kind(a)
+end
diff --git a/flang/unittests/Runtime/Numeric.cpp b/flang/unittests/Runtime/Numeric.cpp
--- a/flang/unittests/Runtime/Numeric.cpp
+++ b/flang/unittests/Runtime/Numeric.cpp
@@ -130,6 +130,21 @@
       RTNAME(SetExponent8)(std::numeric_limits<Real<8>>::quiet_NaN(), 1)));
 }
 
+TEST(Numeric, SelectedIntKind) {
+  std::int8_t r0 = 1;
+  std::int16_t r1 = 3;
+  std::int32_t r2 = 8;
+  std::int64_t r3 = 10;
+  std::int32_t r4 = -10;
+  std::int32_t r5 = 100;
+  EXPECT_EQ(RTNAME(SelectedIntKind)(__FILE__, __LINE__, &r0, 1), 1);
+  EXPECT_EQ(RTNAME(SelectedIntKind)(__FILE__, __LINE__, &r1, 2), 2);
+  EXPECT_EQ(RTNAME(SelectedIntKind)(__FILE__, __LINE__, &r2, 4), 4);
+  EXPECT_EQ(RTNAME(SelectedIntKind)(__FILE__, __LINE__, &r3, 8), 8);
+  EXPECT_EQ(RTNAME(SelectedIntKind)(__FILE__, __LINE__, &r4, 4), 1);
+  EXPECT_EQ(RTNAME(SelectedIntKind)(__FILE__, __LINE__, &r5, 4), -1);
+}
+
 TEST(Numeric, SelectedRealKind) {
   std::int8_t p_s = 1;
   std::int16_t p[11] = {-10, 1, 1, 4, 50, 1, 1, 4, 1, 1, 50};