--- a/browser/components/enterprisepolicies/Policies.jsm
+++ b/browser/components/enterprisepolicies/Policies.jsm
@@ -20,16 +20,20 @@ XPCOMUtils.defineLazyGetter(this, "log",
     prefix: "Policies.jsm",
     // tip: set maxLogLevel to "debug" and use log.debug() to create detailed
     // messages during development. See LOG_LEVELS in Console.jsm for details.
     maxLogLevel: "error",
     maxLogLevelPref: PREF_LOGLEVEL,
   });
 });
 
+XPCOMUtils.defineLazyModuleGetters(this, {
+  PermissionPolicies: "resource:///modules/policies/PermissionPolicies.jsm",
+});
+
 this.EXPORTED_SYMBOLS = ["Policies", "PoliciesValidator"];
 
 this.PoliciesValidator = {
   validateAndParseParameters(param, properties) {
     return validateAndParseParamRecursive(param, properties);
   }
 };
 
@@ -54,16 +58,22 @@ this.Policies = {
   "bookmarks_on_menu": {
     onProfileAfterChange(manager, param) {
       log.debug("Bookmarks to add: ");
       for (let bookmark of param) {
         log.debug("  -> " + bookmark.spec);
       }
     }
   },
+
+  "flash_plugin": {
+    onBeforeUIStartup(manager, param) {
+      PermissionPolicies.addAllowDenyPermissions("plugin:flash", param.allow, param.block);
+    }
+  },
 };
 
 function validateAndParseParamRecursive(param, properties) {
   if (properties.enum) {
     if (properties.enum.includes(param)) {
       return [true, param];
     }
     return [false, null];

new file mode 100644
--- /dev/null
+++ b/browser/components/enterprisepolicies/helpers/PermissionPolicies.jsm
@@ -0,0 +1,39 @@
+/* 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/. */
+
+"use strict";
+
+const Ci = Components.interfaces;
+const Cc = Components.classes;
+const Cr = Components.results;
+const Cu = Components.utils;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+
+this.EXPORTED_SYMBOLS = ["PermissionPolicies"];
+
+this.PermissionPolicies = {
+  addAllowDenyPermissions(permissionName, allowList, blockList) {
+    allowList = allowList || [];
+    blockList = blockList || [];
+
+    for (let origin of allowList) {
+      this._setPermission(origin,
+                          permissionName,
+                          Ci.nsIPermissionManager.ALLOW_ACTION);
+    }
+
+    for (let origin of blockList) {
+      this._setPermission(origin,
+                          permissionName,
+                          Ci.nsIPermissionManager.DENY_ACTION);
+    }
+  },
+
+  _setPermission(uri, name, value) {
+    Services.perms.add(uri, name, value,
+                       Ci.nsIPermissionManager.EXPIRE_POLICY);
+  },
+};

--- a/browser/components/enterprisepolicies/helpers/moz.build
+++ b/browser/components/enterprisepolicies/helpers/moz.build
@@ -1,8 +1,12 @@
 # -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
 # vim: set filetype=python:
 # 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/.
 
 with Files("**"):
     BUG_COMPONENT = ("Firefox", "Enterprise Policies")
+
+EXTRA_JS_MODULES.policies += [
+    'PermissionPolicies.jsm',
+]

--- a/browser/components/enterprisepolicies/schemas/policies.json
+++ b/browser/components/enterprisepolicies/schemas/policies.json
@@ -22,11 +22,33 @@
       "description": "Adds a set of bookmarks to the Bookmarks Menu.",
       "first_available": "59.0",
       "run_on_modified": true,
 
       "type": "array",
       "items": {
         "type": "URL"
       }
+    },
+
+    "flash_plugin": {
+      "description": "Allow or deny flash plugin usage.",
+      "first_available": "60.0",
+
+      "type": "object",
+      "properties": {
+        "allow": {
+          "type": "array",
+          "items": {
+            "type": "origin"
+          }
+        },
+
+        "block": {
+          "type": "array",
+          "items": {
+            "type": "origin"
+          }
+        }
+      }
     }
   }
 }