diff --git a/application/palemoon/components/preferences/security.xul b/application/palemoon/components/preferences/security.xul
index d3d321b16c..d9c3dd55da 100644
--- a/application/palemoon/components/preferences/security.xul
+++ b/application/palemoon/components/preferences/security.xul
@@ -49,6 +49,10 @@
       <preference id="security.cert_pinning.enforcement_level"
                   name="security.cert_pinning.enforcement_level"
                   type="int"/>
+                  
+      <preference id="network.http.opportunistic-encryption"
+                  name="network.http.opportunistic-encryption"
+                  type="bool"/>
       
       <!-- XSS Filter -->
       <!--
@@ -144,6 +148,10 @@
                   oncommand="gSecurityPane.updateHPKPPref();"/>
       </vbox>
     </groupbox>
+    
+    <checkbox id="enableOpEnc"
+              label="&enableOpEnc.label;"
+              preference="network.http.opportunistic-encryption" />
 
     <!-- XSS Filter -->
     <!--
diff --git a/application/palemoon/locales/en-US/chrome/browser/preferences/security.dtd b/application/palemoon/locales/en-US/chrome/browser/preferences/security.dtd
index 2bd3b3aecf..d88c55dc59 100644
--- a/application/palemoon/locales/en-US/chrome/browser/preferences/security.dtd
+++ b/application/palemoon/locales/en-US/chrome/browser/preferences/security.dtd
@@ -40,6 +40,8 @@
 <!ENTITY  enableHPKP.label           "Enable Certificate Key Pinning (HPKP)">
 <!ENTITY  enableHPKP.accesskey       "C">
 
+<!ENTITY  enableOpEnc.label          "Enable Opportunistic Encryption">
+
 <!ENTITY  XSSFilt.label              "XSS Filter">
 <!ENTITY  enableXSSFilt.label        "Enable XSS filter">
 <!ENTITY  enableXSSFilt.accesskey    "f">