diff --git a/src/rules/index.js b/src/rules/index.js
index 3cedbd78..f65d2d86 100644
--- a/src/rules/index.js
+++ b/src/rules/index.js
@@ -33,6 +33,7 @@ import functionNoQuotedStrings from "./function-quote-no-quoted-strings-inside";
 import functionNoUnquotedStrings from "./function-unquote-no-unquoted-strings-inside";
 import mediaFeatureValueDollarVariable from "./media-feature-value-dollar-variable";
 import noDollarVariables from "./no-dollar-variables";
+import mapKeysQuotes from "./map-keys-quotes";
 import noDuplicateDollarVariables from "./no-duplicate-dollar-variables";
 import operatorNoNewlineAfter from "./operator-no-newline-after";
 import operatorNoNewlineBefore from "./operator-no-newline-before";
@@ -77,6 +78,7 @@ export default {
   "double-slash-comment-whitespace-inside": doubleSlashCommentWhitespaceInside,
   "function-quote-no-quoted-strings-inside": functionNoQuotedStrings,
   "function-unquote-no-unquoted-strings-inside": functionNoUnquotedStrings,
+  "map-keys-quotes": mapKeysQuotes,
   "media-feature-value-dollar-variable": mediaFeatureValueDollarVariable,
   "no-dollar-variables": noDollarVariables,
   "no-duplicate-dollar-variables": noDuplicateDollarVariables,
diff --git a/src/rules/map-keys-quotes/README.md b/src/rules/map-keys-quotes/README.md
new file mode 100644
index 00000000..d59cbd88
--- /dev/null
+++ b/src/rules/map-keys-quotes/README.md
@@ -0,0 +1,26 @@
+# map-keys-quotes
+
+All map keys should be quoted.
+
+```scss
+$test: (Helvetica: 14px, Arial: 25px);
+  /**   ↑                ↑
+   * These words should be quoted.
+   */
+```
+
+## Options
+
+### `always`
+
+The following patterns are considered violations:
+
+```scss
+$test: (Helvetica: 14px, Arial: 25px);
+```
+
+The following patterns are _not_ considered violations:
+
+```scss
+$test: ("foo": 14px, "bar": 25px);
+```
diff --git a/src/rules/map-keys-quotes/__tests__/index.js b/src/rules/map-keys-quotes/__tests__/index.js
new file mode 100644
index 00000000..3c5ec988
--- /dev/null
+++ b/src/rules/map-keys-quotes/__tests__/index.js
@@ -0,0 +1,28 @@
+import rule, { ruleName, messages } from "..";
+
+testRule(rule, {
+  ruleName,
+  config: ["always"],
+  syntax: "scss",
+
+  accept: [
+    {
+      code: `
+        $test: ("foo": 14px, "bar": 25px);
+      `,
+      description: "accepts strings without quotes"
+    }
+  ],
+
+  reject: [
+    {
+      code: `
+        $test: (Helvetica: 25px, Arial: 50px)
+      `,
+      message: messages.expected,
+      description:
+        "does not accept variables representing strings that are quoted.",
+      location: 1
+    }
+  ]
+});
diff --git a/src/rules/map-keys-quotes/index.js b/src/rules/map-keys-quotes/index.js
new file mode 100644
index 00000000..cd08ff61
--- /dev/null
+++ b/src/rules/map-keys-quotes/index.js
@@ -0,0 +1,84 @@
+import { utils } from "stylelint";
+import { namespace } from "../../utils";
+import valueParser from "postcss-value-parser";
+
+export const ruleName = namespace("map-keys-quotes");
+
+export const messages = utils.ruleMessages(ruleName, {
+  expected: "Expected keys in map to be quoted."
+});
+
+function rule(primary) {
+  return (root, result) => {
+    const validOptions = utils.validateOptions(result, ruleName, {
+      actual: primary,
+      possible: ["always"]
+    });
+
+    if (!validOptions) {
+      return;
+    }
+
+    root.walkDecls(decl => {
+      if (decl.prop[0] !== "$") {
+        return;
+      }
+
+      valueParser(decl.value).walk(node => {
+        if (
+          node.type === "function" &&
+          node.value === "" &&
+          isMap(node.nodes)
+        ) {
+          // Identify all of the map-keys and see if they're strings (not words).
+          const mapKeys = returnMapKeys(node.nodes);
+
+          mapKeys.forEach(map_key => {
+            if (map_key.type === "word") {
+              utils.report({
+                message: messages.expected,
+                node: decl,
+                result,
+                ruleName
+              });
+            }
+          });
+        }
+      });
+    });
+  };
+}
+
+// Takes in a list of map nodes and identifies if they are a map.
+// A map is identified by the pattern: [string/word colon(div) anything comma(div) ...]
+function isMap(nodes) {
+  if (nodes.length < 4) {
+    return false;
+  }
+
+  if (nodes[0].type !== "word" && nodes[0].type !== "string") {
+    return false;
+  }
+
+  if (nodes[1].value !== ":") {
+    return false;
+  }
+
+  if (nodes[3].value !== ",") {
+    return false;
+  }
+
+  return true;
+}
+
+function returnMapKeys(array) {
+  const new_array = [];
+
+  for (let i = 0; i < array.length; i += 4) {
+    new_array.push(array[i]);
+  }
+
+  return new_array;
+}
+
+export default rule;