diff --git a/lib/plugins/helper/open_graph.js b/lib/plugins/helper/open_graph.js
index 436109114c..3c3b8e381b 100644
--- a/lib/plugins/helper/open_graph.js
+++ b/lib/plugins/helper/open_graph.js
@@ -32,7 +32,7 @@ function openGraphHelper(options = {}) {
   const twitterCard = options.twitter_card || 'summary';
   const date = options.date !== false ? options.date || page.date : false;
   const updated = options.updated !== false ? options.updated || page.updated : false;
-  const language = options.language || page.lang || page.language || config.language;
+  let language = options.language || page.lang || page.language || config.language;
   const author = options.author || config.author;
 
   if (!Array.isArray(images)) images = [images];
@@ -84,7 +84,14 @@ function openGraphHelper(options = {}) {
   }
 
   if (language) {
-    result += og('og:locale', language);
+    if (language.length === 5) {
+      const territory = language.slice(-2);
+      const territoryRegex = new RegExp(territory.concat('$'));
+
+      language = language.replace('-', '_').replace(territoryRegex, territory.toUpperCase());
+
+      result += og('og:locale', language);
+    }
   }
 
   images = images.map(path => {
diff --git a/test/scripts/helpers/open_graph.js b/test/scripts/helpers/open_graph.js
index 9c9d15ef0b..980fa73de0 100644
--- a/test/scripts/helpers/open_graph.js
+++ b/test/scripts/helpers/open_graph.js
@@ -35,7 +35,6 @@ describe('open_graph', () => {
         meta({property: 'og:title', content: hexo.config.title}),
         meta({property: 'og:url'}),
         meta({property: 'og:site_name', content: hexo.config.title}),
-        meta({property: 'og:locale', content: 'en'}),
         meta({property: 'article:published_time', content: post.date.toISOString()}),
         meta({property: 'article:modified_time', content: post.updated.toISOString()}),
         meta({property: 'article:author', content: hexo.config.author}),
@@ -614,7 +613,7 @@ describe('open_graph', () => {
       is_post: isPost
     }, {language: 'es-cr'});
 
-    result.should.contain(meta({property: 'og:locale', content: 'es-cr'}));
+    result.should.contain(meta({property: 'og:locale', content: 'es_CR'}));
   });
 
   it('og:locale - page.lang', () => {
@@ -624,7 +623,7 @@ describe('open_graph', () => {
       is_post: isPost
     });
 
-    result.should.contain(meta({property: 'og:locale', content: 'es-mx'}));
+    result.should.contain(meta({property: 'og:locale', content: 'es_MX'}));
   });
 
   it('og:locale - page.language', () => {
@@ -634,7 +633,7 @@ describe('open_graph', () => {
       is_post: isPost
     });
 
-    result.should.contain(meta({property: 'og:locale', content: 'es-gt'}));
+    result.should.contain(meta({property: 'og:locale', content: 'es_GT'}));
   });
 
   it('og:locale - config.language', () => {
@@ -646,7 +645,19 @@ describe('open_graph', () => {
       is_post: isPost
     });
 
-    result.should.contain(meta({property: 'og:locale', content: 'es-pa'}));
+    result.should.contain(meta({property: 'og:locale', content: 'es_PA'}));
+  });
+
+  it('og:locale - convert territory to uppercase', () => {
+    hexo.config.language = 'fr-fr';
+
+    const result = openGraph.call({
+      page: {},
+      config: hexo.config,
+      is_post: isPost
+    });
+
+    result.should.contain(meta({property: 'og:locale', content: 'fr_FR'}));
   });
 
   it('og:locale - no language set', () => {
@@ -659,6 +670,18 @@ describe('open_graph', () => {
     result.should.not.contain(meta({property: 'og:locale'}));
   });
 
+  it('og:locale - language is not in lang-territory format', () => {
+    hexo.config.language = 'en';
+
+    const result = openGraph.call({
+      page: {},
+      config: hexo.config,
+      is_post: isPost
+    });
+
+    result.should.not.contain(meta({property: 'og:locale'}));
+  });
+
   it('article:author - options.author', () => {
     const result = openGraph.call({
       page: {},