diff --git a/chrome/browser/devtools/devtools_network_transaction.cc b/chrome/browser/devtools/devtools_network_transaction.cc
index 71d37be2135792..982bfab76dda4c 100644
--- a/chrome/browser/devtools/devtools_network_transaction.cc
+++ b/chrome/browser/devtools/devtools_network_transaction.cc
@@ -22,10 +22,6 @@ const char
     DevToolsNetworkTransaction::kDevToolsEmulateNetworkConditionsClientId[] =
         "X-DevTools-Emulate-Network-Conditions-Client-Id";
 
-// Keep in sync with X_DevTools_Request_Id defined in HTTPNames.json5.
-const char DevToolsNetworkTransaction::kDevToolsRequestId[] =
-    "X-DevTools-Request-Id";
-
 DevToolsNetworkTransaction::DevToolsNetworkTransaction(
     DevToolsNetworkController* controller,
     std::unique_ptr<net::HttpTransaction> network_transaction)
@@ -127,7 +123,6 @@ int DevToolsNetworkTransaction::Start(const net::HttpRequestInfo* request,
         kDevToolsEmulateNetworkConditionsClientId, &client_id);
     custom_request_->extra_headers.RemoveHeader(
         kDevToolsEmulateNetworkConditionsClientId);
-    custom_request_->extra_headers.RemoveHeader(kDevToolsRequestId);
 
     if (request_->upload_data_stream) {
       custom_upload_data_stream_.reset(
diff --git a/chrome/browser/devtools/devtools_network_transaction.h b/chrome/browser/devtools/devtools_network_transaction.h
index 85ecc158c8a249..cb13c423c039e5 100644
--- a/chrome/browser/devtools/devtools_network_transaction.h
+++ b/chrome/browser/devtools/devtools_network_transaction.h
@@ -46,7 +46,6 @@ class DevToolsNetworkTransaction
     : public net::HttpTransaction {
  public:
   static const char kDevToolsEmulateNetworkConditionsClientId[];
-  static const char kDevToolsRequestId[];
 
   DevToolsNetworkTransaction(
       DevToolsNetworkController* controller,
diff --git a/headless/public/util/generic_url_request_job.cc b/headless/public/util/generic_url_request_job.cc
index b9a3b68ad8d740..dcc75c2db58b76 100644
--- a/headless/public/util/generic_url_request_job.cc
+++ b/headless/public/util/generic_url_request_job.cc
@@ -32,9 +32,6 @@ bool IsMethodSafe(const std::string& method) {
          method == "TRACE";
 }
 
-// Keep in sync with X_DevTools_Request_Id defined in HTTPNames.json5.
-const char kDevtoolsRequestId[] = "X-DevTools-Request-Id";
-
 }  // namespace
 
 uint64_t GenericURLRequestJob::next_request_id_ = 0;
@@ -66,9 +63,6 @@ void GenericURLRequestJob::SetExtraRequestHeaders(
     const net::HttpRequestHeaders& headers) {
   DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
   extra_request_headers_ = headers;
-
-  // TODO(alexclarke): Remove kDevtoolsRequestId
-  extra_request_headers_.RemoveHeader(kDevtoolsRequestId);
 }
 
 void GenericURLRequestJob::Start() {
diff --git a/third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp b/third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp
index f1a481c35159f7..dc0f1bcb799dcf 100644
--- a/third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp
+++ b/third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp
@@ -703,10 +703,6 @@ void InspectorNetworkAgent::WillSendRequest(
     request.AddHTTPHeaderField(
         HTTPNames::X_DevTools_Emulate_Network_Conditions_Client_Id,
         AtomicString(host_id_));
-
-  request.SetHTTPHeaderField(
-      HTTPNames::X_DevTools_Request_Id,
-      AtomicString(IdentifiersFactory::RequestId(identifier)));
 }
 
 void InspectorNetworkAgent::MarkResourceAsCached(unsigned long identifier) {
diff --git a/third_party/WebKit/Source/platform/loader/fetch/FetchUtils.cpp b/third_party/WebKit/Source/platform/loader/fetch/FetchUtils.cpp
index f9bc710b82cddd..87ca6c590cd241 100644
--- a/third_party/WebKit/Source/platform/loader/fetch/FetchUtils.cpp
+++ b/third_party/WebKit/Source/platform/loader/fetch/FetchUtils.cpp
@@ -100,7 +100,6 @@ bool FetchUtils::IsSimpleHeader(const AtomicString& name,
       EqualIgnoringASCIICase(name, "content-language") ||
       EqualIgnoringASCIICase(
           name, HTTPNames::X_DevTools_Emulate_Network_Conditions_Client_Id) ||
-      EqualIgnoringASCIICase(name, HTTPNames::X_DevTools_Request_Id) ||
       EqualIgnoringASCIICase(name, "save-data"))
     return true;
 
diff --git a/third_party/WebKit/Source/platform/loader/fetch/RawResource.cpp b/third_party/WebKit/Source/platform/loader/fetch/RawResource.cpp
index 87fa5b04962c33..cc24996010f0da 100644
--- a/third_party/WebKit/Source/platform/loader/fetch/RawResource.cpp
+++ b/third_party/WebKit/Source/platform/loader/fetch/RawResource.cpp
@@ -250,12 +250,9 @@ static bool ShouldIgnoreHeaderForCacheReuse(AtomicString header_name) {
   // isn't complete.
   DEFINE_STATIC_LOCAL(
       HashSet<AtomicString>, headers,
-      ({
-          "Cache-Control", "If-Modified-Since", "If-None-Match", "Origin",
-          "Pragma", "Purpose", "Referer", "User-Agent",
-          HTTPNames::X_DevTools_Emulate_Network_Conditions_Client_Id,
-          HTTPNames::X_DevTools_Request_Id,
-      }));
+      ({"Cache-Control", "If-Modified-Since", "If-None-Match", "Origin",
+        "Pragma", "Purpose", "Referer", "User-Agent",
+        HTTPNames::X_DevTools_Emulate_Network_Conditions_Client_Id}));
   return headers.Contains(header_name);
 }
 
diff --git a/third_party/WebKit/Source/platform/loader/fetch/RawResourceTest.cpp b/third_party/WebKit/Source/platform/loader/fetch/RawResourceTest.cpp
index f47eaff5fb35db..6478c904628ff7 100644
--- a/third_party/WebKit/Source/platform/loader/fetch/RawResourceTest.cpp
+++ b/third_party/WebKit/Source/platform/loader/fetch/RawResourceTest.cpp
@@ -587,12 +587,4 @@ TEST_F(RawResourceTest,
                                             FetchInitiatorInfo())));
 }
 
-TEST_F(RawResourceTest, CanReuseDevToolsRequestIdHeader) {
-  ResourceRequest request("data:text/html,");
-  request.SetHTTPHeaderField(HTTPNames::X_DevTools_Request_Id, "12345");
-  Resource* raw = RawResource::Create(request, Resource::kRaw);
-  EXPECT_TRUE(raw->CanReuse(FetchParameters(ResourceRequest("data:text/html,"),
-                                            FetchInitiatorInfo())));
-}
-
 }  // namespace blink
diff --git a/third_party/WebKit/Source/platform/network/HTTPNames.json5 b/third_party/WebKit/Source/platform/network/HTTPNames.json5
index 737294e0d3ded5..5ff112968929e1 100644
--- a/third_party/WebKit/Source/platform/network/HTTPNames.json5
+++ b/third_party/WebKit/Source/platform/network/HTTPNames.json5
@@ -63,7 +63,6 @@
     "X-Content-Type-Options",
     "X-DNS-Prefetch-Control",
     "X-DevTools-Emulate-Network-Conditions-Client-Id",
-    "X-DevTools-Request-Id",
     "X-Frame-Options",
     "X-SourceMap",
     "X-XSS-Protection",