diff --git a/browser/net/brave_ad_block_tp_network_delegate_helper.cc b/browser/net/brave_ad_block_tp_network_delegate_helper.cc
index 448c08296960..ce509b7ad8eb 100644
--- a/browser/net/brave_ad_block_tp_network_delegate_helper.cc
+++ b/browser/net/brave_ad_block_tp_network_delegate_helper.cc
@@ -11,6 +11,7 @@
 #include "brave/browser/brave_browser_process_impl.h"
 #include "brave/common/network_constants.h"
 #include "brave/common/shield_exceptions.h"
+#include "brave/common/url_util.h"
 #include "brave/components/brave_shields/browser/ad_block_regional_service.h"
 #include "brave/components/brave_shields/browser/ad_block_service.h"
 #include "brave/components/brave_shields/browser/brave_shields_util.h"
@@ -97,15 +98,22 @@ void OnBeforeURLRequestAdBlockTPOnTaskRunner(std::shared_ptr<BraveRequestInfo> c
     return;
   }
   DCHECK(ctx->request_identifier != 0);
+
+  // For PDFJS we don't want to treat 2 different URLs as 3p for the main pdf
+  // load which is meant to be top level
+  // chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/https://developer.att.com/.../file.pdf
+  // https://developer.att.com/.../file.pdf
+  // So if the tab origin is chrome-extension, set it to that of the PDF only for PDFJS
+  std::string tab_host = brave::GetURLOrPDFURL(ctx->tab_url).host();
   if (!g_brave_browser_process->tracking_protection_service()->
-      ShouldStartRequest(ctx->request_url, ctx->resource_type, ctx->tab_origin.host())) {
+      ShouldStartRequest(ctx->request_url, ctx->resource_type, tab_host)) {
     ctx->new_url_spec = GetBlankDataURLForResourceType(ctx->resource_type).spec();
     ctx->blocked_by = kTrackerBlocked;
   } else if (!g_brave_browser_process->ad_block_service()->ShouldStartRequest(
-           ctx->request_url, ctx->resource_type, ctx->tab_origin.host()) ||
+           ctx->request_url, ctx->resource_type, tab_host) ||
        !g_brave_browser_process->ad_block_regional_service()
             ->ShouldStartRequest(ctx->request_url, ctx->resource_type,
-                                 ctx->tab_origin.host())) {
+                                 tab_host)) {
     ctx->new_url_spec = GetBlankDataURLForResourceType(ctx->resource_type).spec();
     ctx->blocked_by = kAdBlocked;
   }
diff --git a/browser/net/url_context.cc b/browser/net/url_context.cc
index bdae0568349c..79afcf8c0847 100644
--- a/browser/net/url_context.cc
+++ b/browser/net/url_context.cc
@@ -23,6 +23,7 @@ void BraveRequestInfo::FillCTXFromRequest(const net::URLRequest* request,
     std::shared_ptr<brave::BraveRequestInfo> ctx) {
   ctx->request_identifier = request->identifier();
   ctx->request_url = request->url();
+  ctx->tab_url = request->site_for_cookies();
   ctx->tab_origin = request->site_for_cookies().GetOrigin();
   auto* request_info = content::ResourceRequestInfo::ForRequest(request);
   if (request_info) {
diff --git a/browser/net/url_context.h b/browser/net/url_context.h
index ec71bfd80d3a..ebee381a407f 100644
--- a/browser/net/url_context.h
+++ b/browser/net/url_context.h
@@ -51,6 +51,7 @@ struct BraveRequestInfo {
   ~BraveRequestInfo();
   GURL request_url;
   GURL tab_origin;
+  GURL tab_url;
   std::string new_url_spec;
   bool allow_brave_shields = true;
   bool allow_ads = false;
diff --git a/common/BUILD.gn b/common/BUILD.gn
index c194b5a5a8f0..e6087d5df90b 100644
--- a/common/BUILD.gn
+++ b/common/BUILD.gn
@@ -49,6 +49,8 @@ source_set("common") {
       "shield_exceptions.h",
       "url_constants.cc",
       "url_constants.h",
+      "url_util.cc",
+      "url_util.h",
     ]
 
     public_deps = [
diff --git a/common/extensions/extension_constants.cc b/common/extensions/extension_constants.cc
index bebb46369019..8208f67e2ea5 100644
--- a/common/extensions/extension_constants.cc
+++ b/common/extensions/extension_constants.cc
@@ -14,3 +14,4 @@ const char crl_set_extension_id[] = "hfnkpimlhhgieaddgfemjhofmfblmnib";
 const char pdfjs_extension_id[] = "oemmndcbldboiebfnladdacbdfmadadm";
 const char pdfjs_extension_name[] = "PDF Viewer (PDF.js)";
 const char pdfjs_extension_public_key[] = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDb5PIb8ayK6vHvEIY1nJKRSCDE8iJ1T43qFN+5dvCVQrmyEkgqB9ZuZNT24Lwot96HV51VoITHKRNIVKI2Nrbfn0M49t7qtaP34g/GXJ7mAIbSzsY4+i+Wsz8EL2SNEIw6uH8RmXG7nZ29NJ7sk7jn17QmMsO2UJ01UT8hfOOOEQIDAQAB";
+const char pdfjs_extension_origin[] = "chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/";
diff --git a/common/extensions/extension_constants.h b/common/extensions/extension_constants.h
index 4ab3451b655c..185ab03026cf 100644
--- a/common/extensions/extension_constants.h
+++ b/common/extensions/extension_constants.h
@@ -12,3 +12,4 @@ extern const char crl_set_extension_id[];
 extern const char pdfjs_extension_id[];
 extern const char pdfjs_extension_name[];
 extern const char pdfjs_extension_public_key[];
+extern const char pdfjs_extension_origin[];
diff --git a/common/url_util.cc b/common/url_util.cc
new file mode 100644
index 000000000000..9609f687998f
--- /dev/null
+++ b/common/url_util.cc
@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "brave/common/url_util.h"
+
+#include <string>
+
+#include "brave/common/extensions/extension_constants.h"
+#include "url/gurl.h"
+
+namespace brave {
+
+GURL GetURLOrPDFURL(const GURL& url) {
+  if (url.SchemeIs("chrome-extension") &&
+      url.host() == pdfjs_extension_id) {
+    static size_t pdfjs_substring_len = std::string(pdfjs_extension_origin).length();
+    size_t http_pos = url.spec().find(std::string(pdfjs_extension_origin) + "http://");
+    size_t https_pos = url.spec().find(std::string(pdfjs_extension_origin) + "https://");
+    if (http_pos != std::string::npos || https_pos != std::string::npos) {
+      return GURL(url.spec().substr(pdfjs_substring_len,
+          url.spec().length() - pdfjs_substring_len));
+    }
+  }
+  return url;
+}
+
+}  // namespace brave
diff --git a/common/url_util.h b/common/url_util.h
new file mode 100644
index 000000000000..2f8a15ab5eda
--- /dev/null
+++ b/common/url_util.h
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef BRAVE_COMMON_URL_UTIL_H_
+#define BRAVE_COMMON_URL_UTIL_H_
+
+class GURL;
+
+namespace brave {
+
+// Returns the location of the PDF if this URL is a PDFJS extension URL.
+// Otherwise simply just returns the same URL as passed in.
+GURL GetURLOrPDFURL(const GURL& url);
+
+}  // namespace brave
+
+#endif  // BRAVE_COMMON_URL_UTIL_H_
diff --git a/common/url_util_unittest.cc b/common/url_util_unittest.cc
new file mode 100644
index 000000000000..673ab9c24e3b
--- /dev/null
+++ b/common/url_util_unittest.cc
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "brave/common/url_util.h"
+#include "chrome/test/base/chrome_render_view_host_test_harness.h"
+#include "url/gurl.h"
+
+typedef testing::Test BraveUrlUtilTest;
+
+namespace brave {
+
+TEST_F(BraveUrlUtilTest, GetURLOrPDFURL) {
+  std::vector<GURL> unchanged_urls({
+    // PDFJS URL but not to a PDF
+    GURL("chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/test.html"),
+    // PDFJS ID but not chrome-extension scheme
+    GURL("chrome://oemmndcbldboiebfnladdacbdfmadadm/https://test.html"),
+    // Not PDFJS ID but format of a PDFJS PDF URL
+    GURL("chrome-extension://aaamndcbldboiebfnladdacbdfmadaaa/https://example.com/test.html"),
+    // Random other URL
+    GURL("https://example.com")
+  });
+  std::for_each(unchanged_urls.begin(), unchanged_urls.end(),
+      [this](GURL url){
+    EXPECT_EQ(brave::GetURLOrPDFURL(url), url);
+  });
+  EXPECT_EQ(brave::GetURLOrPDFURL(GURL("chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/http://example.com?test")),
+      GURL("http://example.com?test"));
+  EXPECT_EQ(brave::GetURLOrPDFURL(GURL("chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/https://example.com?test")),
+      GURL("https://example.com?test"));
+}
+
+}  // namespace
diff --git a/test/BUILD.gn b/test/BUILD.gn
index 1cbb1d4eb6be..60fd688f9a26 100644
--- a/test/BUILD.gn
+++ b/test/BUILD.gn
@@ -50,7 +50,7 @@ test("brave_unit_tests") {
     "//brave/browser/resources/settings/reset_report_uploader_unittest.cc",
     "//brave/chromium_src/chrome/browser/external_protocol/external_protocol_handler_unittest.cc",
     "//brave/chromium_src/chrome/browser/signin/account_consistency_disabled_unittest.cc",
-    "//brave\chromium_src/chrome/browser/ui/bookmarks/brave_bookmark_context_menu_controller_unittest.cc",
+    "//brave/chromium_src/chrome/browser/ui/bookmarks/brave_bookmark_context_menu_controller_unittest.cc",
     "//brave/chromium_src/components/search_engines/brave_template_url_prepopulate_data_unittest.cc",
     "//brave/chromium_src/components/search_engines/brave_template_url_service_util_unittest.cc",
     "//brave/chromium_src/components/version_info/brave_version_info_unittest.cc",
@@ -59,6 +59,7 @@ test("brave_unit_tests") {
     "//brave/common/shield_exceptions_unittest.cc",
     "//brave/common/tor/tor_test_constants.cc",
     "//brave/common/tor/tor_test_constants.h",
+    "//brave/common/url_util_unittest.cc",
     "//brave/components/assist_ranker/ranker_model_loader_impl_unittest.cc",
     "//brave/components/brave_shields/browser/ad_block_regional_service_unittest.cc",
     "//brave/components/brave_sync/bookmark_order_util_unittest.cc",