diff --git a/build/dart/dart_action.gni b/build/dart/dart_action.gni
index 334a09a8f20..0643c872a89 100644
--- a/build/dart/dart_action.gni
+++ b/build/dart/dart_action.gni
@@ -363,7 +363,7 @@ template("dart_action") {
 #    The arguments to pass to the Dart script.
 #
 #  packages (optional):
-#    The un-rebased path to the .packages file.
+#    The un-rebased path to the package_config.json file.
 #
 #  Forwarded to action() with the usual meaning:
 #    depfile
diff --git a/pkg/compiler/testing.json b/pkg/compiler/testing.json
index 78859805cb6..923911a7ab7 100644
--- a/pkg/compiler/testing.json
+++ b/pkg/compiler/testing.json
@@ -3,7 +3,7 @@
 "":"for details. All rights reserved. Use of this source code is governed by a",
 "":"BSD-style license that can be found in the LICENSE.md file.",
 
-  "packages": "../../.packages",
+  "packages": "../../.dart_tool/package_config.json",
 
   "analyze": {
     "options": "analysis_options.yaml",
diff --git a/pkg/dev_compiler/test/sourcemap/testing.json b/pkg/dev_compiler/test/sourcemap/testing.json
index 03c27221bf7..5f6e6a8f144 100644
--- a/pkg/dev_compiler/test/sourcemap/testing.json
+++ b/pkg/dev_compiler/test/sourcemap/testing.json
@@ -2,7 +2,7 @@
 "":"Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file",
 "":"for details. All rights reserved. Use of this source code is governed by a",
 "":"BSD-style license that can be found in the LICENSE.md file.",
-  "packages": "../../../../.packages",
+  "packages": "../../../../.dart_tool/package_config.json",
   "suites": [
     {
       "name": "sourcemaps_ddk",
diff --git a/pkg/front_end/test/fasta/parser/testing.json b/pkg/front_end/test/fasta/parser/testing.json
index b3ae4c8770c..8265d1e4379 100644
--- a/pkg/front_end/test/fasta/parser/testing.json
+++ b/pkg/front_end/test/fasta/parser/testing.json
@@ -2,7 +2,7 @@
 "":"Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file",
 "":"for details. All rights reserved. Use of this source code is governed by a",
 "":"BSD-style license that can be found in the LICENSE.md file.",
-  "packages": "../../../../../.packages",
+  "packages": "../../../../../.dart_tool/package_config.json",
   "suites": [
     {
       "name": "parser",
diff --git a/pkg/front_end/test/fasta/scanner/testing.json b/pkg/front_end/test/fasta/scanner/testing.json
index be732cb23d5..711f0cf6502 100644
--- a/pkg/front_end/test/fasta/scanner/testing.json
+++ b/pkg/front_end/test/fasta/scanner/testing.json
@@ -2,7 +2,7 @@
 "":"Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file",
 "":"for details. All rights reserved. Use of this source code is governed by a",
 "":"BSD-style license that can be found in the LICENSE.md file.",
-  "packages": "../../../../../.packages",
+  "packages": "../../../../../.dart_tool/package_config.json",
   "suites": [
     {
       "name": "scanner",
diff --git a/pkg/front_end/test/lint_suite.dart b/pkg/front_end/test/lint_suite.dart
index af61e9a3bb2..130a4529de5 100644
--- a/pkg/front_end/test/lint_suite.dart
+++ b/pkg/front_end/test/lint_suite.dart
@@ -169,7 +169,8 @@ class LintStep extends Step<LintTestDescription, LintTestDescription, Context> {
       description.cache.firstToken = scanner.tokenize();
       description.cache.lineStarts = scanner.lineStarts;
 
-      Uri dotPackages = description.uri.resolve(".packages");
+      Uri dotPackages =
+          description.uri.resolve(".dart_tool/package_config.json");
       while (true) {
         if (new File.fromUri(dotPackages).existsSync()) {
           break;
@@ -178,7 +179,8 @@ class LintStep extends Step<LintTestDescription, LintTestDescription, Context> {
         if (dotPackages.pathSegments.length < Uri.base.pathSegments.length) {
           break;
         }
-        dotPackages = dotPackages.resolve("../.packages");
+        dotPackages =
+            dotPackages.resolve("../../.dart_tool/package_config.json");
       }
 
       File dotPackagesFile = new File.fromUri(dotPackages);
diff --git a/pkg/front_end/testing.json b/pkg/front_end/testing.json
index 8c5b79ebb07..63cd5dbcc8e 100644
--- a/pkg/front_end/testing.json
+++ b/pkg/front_end/testing.json
@@ -2,7 +2,7 @@
   "": "Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file",
   "": "for details. All rights reserved. Use of this source code is governed by a",
   "": "BSD-style license that can be found in the LICENSE.md file.",
-  "packages": "../../.packages",
+  "packages": "../../.dart_tool/package_config.json",
   "suites": [
     {
       "name": "messages",
diff --git a/pkg/front_end/testing_with_lints.json b/pkg/front_end/testing_with_lints.json
index 6cdef88164b..4570a3998ff 100644
--- a/pkg/front_end/testing_with_lints.json
+++ b/pkg/front_end/testing_with_lints.json
@@ -3,7 +3,7 @@
 "ignored_2":"for details. All rights reserved. Use of this source code is governed by a",
 "ignored_3":"BSD-style license that can be found in the LICENSE.md file.",
 
-  "packages": "../../.packages",
+  "packages": "../../.dart_tool/package_config.json",
   "analyze": {
     "options": "analysis_options.yaml",
     "uris": [
diff --git a/pkg/testing/testing.json b/pkg/testing/testing.json
index 722834dd8ba..78faafc3cdb 100644
--- a/pkg/testing/testing.json
+++ b/pkg/testing/testing.json
@@ -3,7 +3,7 @@
 "":"for details. All rights reserved. Use of this source code is governed by a",
 "":"BSD-style license that can be found in the LICENSE.md file.",
 
-  "packages": "../../.packages",
+  "packages": "../../.dart_tool/package_config.json",
 
   "suites": [
     {
diff --git a/runtime/observatory/BUILD.gn b/runtime/observatory/BUILD.gn
index 80b6d6e81bb..86647e82924 100644
--- a/runtime/observatory/BUILD.gn
+++ b/runtime/observatory/BUILD.gn
@@ -13,7 +13,7 @@ prebuilt_dart2js_action("build_observatory") {
 
   # dart2js produces a .deps file, but it is not in a format that is understood
   # by ninja, so we explicitly list all the sources here.
-  inputs = [ "../../.packages" ] + observatory_sources
+  inputs = [ "../../.dart_tool/package_config.json" ] + observatory_sources
 
   output = "$target_gen_dir/observatory/web/main.dart.js"
   outputs = [ output ]
@@ -24,7 +24,7 @@ prebuilt_dart2js_action("build_observatory") {
   args = [
     "-o",
     rebase_path(output),
-    "--packages=" + rebase_path("../../.packages"),
+    "--packages=" + rebase_path("../../.dart_tool/package_config.json"),
     "--no-sound-null-safety",
   ]
   if (is_debug) {
diff --git a/runtime/observatory_2/BUILD.gn b/runtime/observatory_2/BUILD.gn
index 412e378f7e4..b21c2f0007a 100644
--- a/runtime/observatory_2/BUILD.gn
+++ b/runtime/observatory_2/BUILD.gn
@@ -13,7 +13,7 @@ prebuilt_dart2js_action("build_observatory") {
 
   # dart2js produces a .deps file, but it is not in a format that is understood
   # by ninja, so we explicitly list all the sources here.
-  inputs = [ "../../.packages" ] + observatory_sources
+  inputs = [ "../../.dart_tool/package_config.json" ] + observatory_sources
 
   output = "$target_gen_dir/observatory/web/main.dart.js"
   outputs = [ output ]
@@ -24,7 +24,7 @@ prebuilt_dart2js_action("build_observatory") {
   args = [
     "-o",
     rebase_path(output),
-    "--packages=" + rebase_path("../../.packages"),
+    "--packages=" + rebase_path("../../.dart_tool/package_config.json"),
   ]
   if (is_debug) {
     args += [ "--enable-asserts" ]
diff --git a/tools/bots/flutter/compile_flutter.sh b/tools/bots/flutter/compile_flutter.sh
index 35c3e8157c4..511855c401f 100755
--- a/tools/bots/flutter/compile_flutter.sh
+++ b/tools/bots/flutter/compile_flutter.sh
@@ -83,7 +83,7 @@ popd  # src
 mkdir flutter_patched_sdk
 
 $checkout/tools/sdks/dart-sdk/bin/dart \
-    --packages=$checkout/.packages \
+    --packages=$checkout/.dart_tool/package_config.json \
     $checkout/pkg/front_end/tool/_fasta/compile_platform.dart \
     dart:core \
     -Ddart.vm.product=false \
@@ -97,7 +97,7 @@ $checkout/tools/sdks/dart-sdk/bin/dart \
     vm_outline_strong.dill
 
 $checkout/tools/sdks/dart-sdk/bin/dart \
-    --packages=$checkout/.packages \
+    --packages=$checkout/.dart_tool/package_config.json \
     $checkout/pkg/front_end/tool/_fasta/compile_platform.dart \
     --nnbd-agnostic \
     --target=flutter \
diff --git a/utils/compile_platform.gni b/utils/compile_platform.gni
index 37c340726b1..0523ac32039 100644
--- a/utils/compile_platform.gni
+++ b/utils/compile_platform.gni
@@ -46,7 +46,7 @@ template("compile_platform") {
     }
     script = "$_dart_root/pkg/front_end/tool/_fasta/compile_platform.dart"
 
-    packages = "$_dart_root/.packages"
+    packages = "$_dart_root/.dart_tool/package_config.json"
 
     outputs = invoker.outputs
 
diff --git a/utils/compiler/BUILD.gn b/utils/compiler/BUILD.gn
index e724494d920..90190b80e7a 100644
--- a/utils/compiler/BUILD.gn
+++ b/utils/compiler/BUILD.gn
@@ -41,7 +41,7 @@ prebuilt_dart_action("dart2js_create_snapshot_entry") {
 
   outputs = [ "$target_gen_dir/dart2js.dart" ]
 
-  packages = "../../.packages"
+  packages = "../../.dart_tool/package_config.json"
 
   args = [ "--output_dir=$output_dir" ]
 }
@@ -63,7 +63,7 @@ application_snapshot("dart2js") {
   vm_args = []
   main_dart = "$target_gen_dir/dart2js.dart"
   training_args = [
-    "--packages=" + rebase_path("../../.packages"),
+    "--packages=" + rebase_path("../../.dart_tool/package_config.json"),
     "--libraries-spec=" + rebase_path("$sdk_root/lib/libraries.json"),
 
     # Specifying the platform explicitly elides running the CFE on the sdk
diff --git a/utils/dartanalyzer/BUILD.gn b/utils/dartanalyzer/BUILD.gn
index b7d2486db88..87291fd93c9 100644
--- a/utils/dartanalyzer/BUILD.gn
+++ b/utils/dartanalyzer/BUILD.gn
@@ -40,7 +40,7 @@ prebuilt_dart_action("generate_summary_strong") {
     "../../sdk:write_version_file",
   ]
   script = "../../pkg/analyzer/tool/summary/build_sdk_summaries.dart"
-  packages = "../../.packages"
+  packages = "../../.dart_tool/package_config.json"
   output = "$root_gen_dir/strong.sum"
   outputs = [ output ]
   vm_args = [ "-Dsdk_hash=$sdk_hash" ]
diff --git a/utils/dartdevc/BUILD.gn b/utils/dartdevc/BUILD.gn
index 74c0cc3b529..67e0411e3c6 100644
--- a/utils/dartdevc/BUILD.gn
+++ b/utils/dartdevc/BUILD.gn
@@ -59,7 +59,7 @@ template("dart2js_compile") {
 
     script = "../../pkg/compiler/lib/src/dart2js.dart"
 
-    packages = "../../.packages"
+    packages = "../../.dart_tool/package_config.json"
 
     vm_args = [ "-Dsdk_hash=$sdk_hash" ]
 
diff --git a/utils/gen_kernel/BUILD.gn b/utils/gen_kernel/BUILD.gn
index 0df57228e7f..8206342af42 100644
--- a/utils/gen_kernel/BUILD.gn
+++ b/utils/gen_kernel/BUILD.gn
@@ -14,7 +14,7 @@ prebuilt_dart_action("bootstrap_gen_kernel") {
   ]
   gen_kernel_script = "$_dart_root/pkg/vm/bin/gen_kernel.dart"
   platform_dill = "$root_out_dir/vm_platform_strong.dill"
-  dot_packages = rebase_path("$_dart_root/.packages")
+  dot_packages = rebase_path("$_dart_root/.dart_tool/package_config.json")
 
   inputs = [
     gen_kernel_script,
diff --git a/utils/kernel-service/BUILD.gn b/utils/kernel-service/BUILD.gn
index 4d464c4f3cb..506dd494350 100644
--- a/utils/kernel-service/BUILD.gn
+++ b/utils/kernel-service/BUILD.gn
@@ -101,7 +101,7 @@ template("kernel_service_dill") {
           # consuming/producing kernel.
           "-Dsdk_hash=$sdk_hash",
 
-          "--packages=" + scheme + ":///.packages",
+          "--packages=" + scheme + ":///.dart_tool/package_config.json",
           "--platform=" + rebase_path("$root_out_dir/vm_platform_strong.dill"),
           "--filesystem-root=" + rebase_path("../../"),
           "--filesystem-scheme=" + scheme,