diff --git a/flang/docs/IntrinsicTypes.md b/flang/docs/IntrinsicTypes.md
--- a/flang/docs/IntrinsicTypes.md
+++ b/flang/docs/IntrinsicTypes.md
@@ -73,8 +73,7 @@
 
 #### Modifying the default kind with default-integer-8:  
 INTEGER 8
-
-There is no option to modify the default logical kind.
+LOGICAL 8
 
 Modules compiled with different default-real and default-integer kinds
 may be freely mixed.
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -704,6 +704,7 @@
     res.getDefaultKinds().set_defaultIntegerKind(8);
     res.getDefaultKinds().set_subscriptIntegerKind(8);
     res.getDefaultKinds().set_sizeIntegerKind(8);
+    res.getDefaultKinds().set_defaultLogicalKind(8);
   }
   if (args.hasArg(clang::driver::options::OPT_fdefault_double_8)) {
     if (!args.hasArg(clang::driver::options::OPT_fdefault_real_8)) {
diff --git a/flang/test/Lower/Intrinsics/get_environment_variable.f90 b/flang/test/Lower/Intrinsics/get_environment_variable.f90
--- a/flang/test/Lower/Intrinsics/get_environment_variable.f90
+++ b/flang/test/Lower/Intrinsics/get_environment_variable.f90
@@ -82,7 +82,8 @@
 
 ! CHECK-LABEL: func @_QPname_and_trim_name_only(
 ! CHECK-SAME: %[[nameArg:.*]]: !fir.boxchar<1> {fir.bindc_name = "name"},
-! CHECK-SAME: %[[trimNameArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_name = "trim_name"}) {
+! CHECK-32-SAME: %[[trimNameArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_name = "trim_name"}) {
+! CHECK-64-SAME: %[[trimNameArg:.*]]: !fir.ref<!fir.logical<8>> {fir.bindc_name = "trim_name"}) {
 subroutine name_and_trim_name_only(name, trim_name)
     character(len=32) :: name
     logical :: trim_name
@@ -120,7 +121,8 @@
 ! CHECK-SAME: %[[valueArg:.*]]: !fir.boxchar<1> {fir.bindc_name = "value"},
 ! CHECK-SAME: %[[lengthArg:[^:]*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_name = "length"},
 ! CHECK-SAME: %[[statusArg:.*]]: !fir.ref<i[[DEFAULT_INTEGER_SIZE]]> {fir.bindc_name = "status"},
-! CHECK-SAME: %[[trimNameArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_name = "trim_name"},
+! CHECK-32-SAME: %[[trimNameArg:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_name = "trim_name"},
+! CHECK-64-SAME: %[[trimNameArg:.*]]: !fir.ref<!fir.logical<8>> {fir.bindc_name = "trim_name"},
 ! CHECK-SAME: %[[errmsgArg:.*]]: !fir.boxchar<1> {fir.bindc_name = "errmsg"}) {
 subroutine all_arguments(name, value, length, status, trim_name, errmsg)
     character(len=32) :: name, value, errmsg
@@ -138,15 +140,17 @@
 ! CHECK-NEXT: %[[lengthBoxed:.*]] = fir.embox %[[lengthArg]] : (!fir.ref<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<i[[DEFAULT_INTEGER_SIZE]]>
 ! CHECK-NEXT: %[[errmsgBoxed:.*]] = fir.embox %[[errmsgCast]] : (!fir.ref<!fir.char<1,32>>) -> !fir.box<!fir.char<1,32>>
 ! CHECK:      %[[trimName:.*]] = fir.if %{{.*}} -> (i1) {
-! CHECK-NEXT:   %[[trimNameLoaded:.*]] = fir.load %[[trimNameArg]] : !fir.ref<!fir.logical<4>>
-! CHECK-NEXT:   %[[trimCast:.*]] = fir.convert %[[trimNameLoaded]] : (!fir.logical<4>) -> i1
+! CHECK-32-NEXT:   %[[trimNameLoaded:.*]] = fir.load %[[trimNameArg]] : !fir.ref<!fir.logical<4>>
+! CHECK-64-NEXT:   %[[trimNameLoaded:.*]] = fir.load %[[trimNameArg]] : !fir.ref<!fir.logical<8>>
+! CHECK-32-NEXT:   %[[trimCast:.*]] = fir.convert %[[trimNameLoaded]] : (!fir.logical<4>) -> i1
+! CHECK-64-NEXT:   %[[trimCast:.*]] = fir.convert %[[trimNameLoaded]] : (!fir.logical<8>) -> i1
 ! CHECK-NEXT:   fir.result %[[trimCast]] : i1
 ! CHECK-NEXT: } else {
 ! CHECK-NEXT:   %[[trueVal:.*]] = arith.constant true
 ! CHECK-NEXT:   fir.result %[[trueVal]] : i1
 ! CHECK-NEXT: }
 ! CHECK: %[[sourceFileString:.*]] = fir.address_of(@_QQcl.[[fileString:.*]]) : !fir.ref<!fir.char<1,[[fileStringLength:.*]]>>
-! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 20]] : i32
+! CHECK-NEXT: %[[sourceLine:.*]] = arith.constant [[# @LINE - 22]] : i32
 ! CHECK-NEXT: %[[name:.*]] = fir.convert %[[nameBoxed]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
 ! CHECK-NEXT: %[[value:.*]] = fir.convert %[[valueBoxed]] : (!fir.box<!fir.char<1,32>>) -> !fir.box<none>
 ! CHECK-NEXT: %[[length:.*]] = fir.convert %[[lengthBoxed]] : (!fir.box<i[[DEFAULT_INTEGER_SIZE]]>) -> !fir.box<none>
diff --git a/flang/tools/f18-parse-demo/f18-parse-demo.cpp b/flang/tools/f18-parse-demo/f18-parse-demo.cpp
--- a/flang/tools/f18-parse-demo/f18-parse-demo.cpp
+++ b/flang/tools/f18-parse-demo/f18-parse-demo.cpp
@@ -405,6 +405,7 @@
       defaultKinds.set_defaultRealKind(8);
     } else if (arg == "-i8" || arg == "-fdefault-integer-8") {
       defaultKinds.set_defaultIntegerKind(8);
+      defaultKinds.set_defaultLogicalKind(8);
     } else if (arg == "-help" || arg == "--help" || arg == "-?") {
       llvm::errs()
           << "f18-parse-demo options:\n"