diff --git a/package.json b/package.json
index 6e3c45f..ab4c2a8 100644
--- a/package.json
+++ b/package.json
@@ -60,7 +60,7 @@
     "eslint-plugin-promise": "^3.6.0",
     "eslint-plugin-standard": "^3.0.1",
     "lerna": "^2.0.0",
-    "mocha": "^4.0.1",
+    "mocha": "^5.0.5",
     "mocha-lcov-reporter": "^1.3.0",
     "nyc": "^11.3.0",
     "remark": "^8.0.0",
diff --git a/yarn.lock b/yarn.lock
index 4ab7556..202a415 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -765,9 +765,9 @@ braces@^1.8.2:
     preserve "^0.2.0"
     repeat-element "^1.1.2"
 
-browser-stdout@1.3.0:
-  version "1.3.0"
-  resolved "https://registry.yarnpkg.com/browser-stdout/-/browser-stdout-1.3.0.tgz#f351d32969d32fa5d7a5567154263d928ae3bd1f"
+browser-stdout@1.3.1:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/browser-stdout/-/browser-stdout-1.3.1.tgz#baa559ee14ced73452229bad7326467c61fabd60"
 
 builtin-modules@^1.0.0, builtin-modules@^1.1.1:
   version "1.1.1"
@@ -1440,9 +1440,9 @@ detect-indent@^5.0.0:
   version "5.0.0"
   resolved "https://registry.yarnpkg.com/detect-indent/-/detect-indent-5.0.0.tgz#3871cc0a6a002e8c3e5b3cf7f336264675f06b9d"
 
-diff@3.3.1:
-  version "3.3.1"
-  resolved "https://registry.yarnpkg.com/diff/-/diff-3.3.1.tgz#aa8567a6eed03c531fc89d3f711cd0e5259dec75"
+diff@3.5.0:
+  version "3.5.0"
+  resolved "https://registry.yarnpkg.com/diff/-/diff-3.5.0.tgz#800c0dd1e0a8bfbc95835c202ad220fe317e5a12"
 
 doctrine@1.5.0:
   version "1.5.0"
@@ -2983,14 +2983,14 @@ mocha-lcov-reporter@^1.3.0:
   version "1.3.0"
   resolved "https://registry.yarnpkg.com/mocha-lcov-reporter/-/mocha-lcov-reporter-1.3.0.tgz#469bdef4f8afc9a116056f079df6182d0afb0384"
 
-mocha@^4.0.1:
-  version "4.0.1"
-  resolved "https://registry.yarnpkg.com/mocha/-/mocha-4.0.1.tgz#0aee5a95cf69a4618820f5e51fa31717117daf1b"
+mocha@^5.0.5:
+  version "5.0.5"
+  resolved "https://registry.yarnpkg.com/mocha/-/mocha-5.0.5.tgz#e228e3386b9387a4710007a641f127b00be44b52"
   dependencies:
-    browser-stdout "1.3.0"
+    browser-stdout "1.3.1"
     commander "2.11.0"
     debug "3.1.0"
-    diff "3.3.1"
+    diff "3.5.0"
     escape-string-regexp "1.0.5"
     glob "7.1.2"
     growl "1.10.3"