diff --git a/changelog_unreleased/scss/10005.md b/changelog_unreleased/scss/10005.md
new file mode 100644
index 000000000..17b441df8
--- /dev/null
+++ b/changelog_unreleased/scss/10005.md
@@ -0,0 +1,17 @@
+#### Fix maps with keys that are lists or maps (#10005 by @fisker)
+
+<!-- prettier-ignore -->
+```scss
+// Input
+$map: (
+  ('my list'): 'hello world',
+);
+
+// Prettier stable
+TypeError: Cannot read property 'length' of undefined
+
+// Prettier main
+$map: (
+  ("my list"): "hello world",
+);
+```
diff --git a/src/language-css/printer-postcss.js b/src/language-css/printer-postcss.js
index b21297d1c..10a2f0971 100644
--- a/src/language-css/printer-postcss.js
+++ b/src/language-css/printer-postcss.js
@@ -57,6 +57,7 @@ const {
   hasParensAroundNode,
   hasEmptyRawBefore,
   isKeyValuePairNode,
+  isKeyInValuePairNode,
   isDetachedRulesetCallNode,
   isTemplatePlaceholderNode,
   isTemplatePropNode,
@@ -856,8 +857,9 @@ function genericPrint(path, options, print) {
 
       const lastItem = node.groups[node.groups.length - 1];
       const isLastItemComment = lastItem && lastItem.type === "value-comment";
+      const isKey = isKeyInValuePairNode(node, parentNode);
 
-      return group(
+      const printed = group(
         [
           node.open ? path.call(print, "open") : "",
           indent([
@@ -873,6 +875,7 @@ function genericPrint(path, options, print) {
                   isKeyValuePairNode(node) &&
                   node.type === "value-comma_group" &&
                   node.groups &&
+                  node.groups[0].type !== "value-paren_group" &&
                   node.groups[2] &&
                   node.groups[2].type === "value-paren_group"
                 ) {
@@ -898,9 +901,11 @@ function genericPrint(path, options, print) {
           node.close ? path.call(print, "close") : "",
         ],
         {
-          shouldBreak: isSCSSMapItem,
+          shouldBreak: isSCSSMapItem && !isKey,
         }
       );
+
+      return isKey ? dedent(printed) : printed;
     }
     case "value-func": {
       return [
@@ -934,7 +939,9 @@ function genericPrint(path, options, print) {
       return [
         node.value,
         // Don't add spaces on escaped colon `:`, e.g: grid-template-rows: [row-1-00\:00] auto;
-        (prevNode && prevNode.value[prevNode.value.length - 1] === "\\") ||
+        (prevNode &&
+          typeof prevNode.value === "string" &&
+          prevNode.value[prevNode.value.length - 1] === "\\") ||
         // Don't add spaces on `:` in `url` function (i.e. `url(fbglyph: cross-outline, fig-white)`)
         insideValueFunctionNode(path, "url")
           ? ""
diff --git a/src/language-css/utils.js b/src/language-css/utils.js
index 20e1bff38..1843cffde 100644
--- a/src/language-css/utils.js
+++ b/src/language-css/utils.js
@@ -401,7 +401,22 @@ function isWordNode(node) {
 }
 
 function isColonNode(node) {
-  return node.type === "value-colon";
+  return node && node.type === "value-colon";
+}
+
+function isKeyInValuePairNode(node, parentNode) {
+  if (!isKeyValuePairNode(parentNode)) {
+    return false;
+  }
+
+  const { groups } = parentNode;
+  const index = groups.indexOf(node);
+
+  if (index === -1) {
+    return false;
+  }
+
+  return isColonNode(groups[index + 1]);
 }
 
 function isMediaAndSupportsKeywords(node) {
@@ -503,6 +518,7 @@ module.exports = {
   isPostcssSimpleVarNode,
   isKeyValuePairNode,
   isKeyValuePairInParenGroupNode,
+  isKeyInValuePairNode,
   isSCSSMapItemNode,
   isInlineValueCommentNode,
   isHashNode,
diff --git a/tests/scss/map/__snapshots__/jsfmt.spec.js.snap b/tests/scss/map/__snapshots__/jsfmt.spec.js.snap
new file mode 100644
index 000000000..729e8d5a7
--- /dev/null
+++ b/tests/scss/map/__snapshots__/jsfmt.spec.js.snap
@@ -0,0 +1,261 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`key-values.scss - {"trailingComma":"none"} format 1`] = `
+====================================options=====================================
+parsers: ["scss"]
+printWidth: 80
+trailingComma: "none"
+                                                                                | printWidth
+=====================================input======================================
+$map: (
+  ('key': 'value', 'key': 'value','key': 'value','key': 'value','key': 'value',):
+  ('key': 'value',),
+  ('key': 'value', 'key': 'value','key': 'value','key': 'value','key': 'value',):
+  ('list'),
+  ('list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list'):
+  ('list'),
+  ('list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list'):
+  ('key': 'value',),
+  ('key': 'value', 'key': 'value','key': 'value','key': 'value','key': 'value',):
+  1,
+);
+
+=====================================output=====================================
+$map: (
+  (
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value"
+  ):
+    (
+      "key": "value"
+    ),
+  (
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value"
+  ):
+    (
+      "list"
+    ),
+  (
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list"
+  ):
+    (
+      "list"
+    ),
+  (
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list"
+  ):
+    (
+      "key": "value"
+    ),
+  (
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value"
+  ):
+    1
+);
+
+================================================================================
+`;
+
+exports[`key-values.scss format 1`] = `
+====================================options=====================================
+parsers: ["scss"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+$map: (
+  ('key': 'value', 'key': 'value','key': 'value','key': 'value','key': 'value',):
+  ('key': 'value',),
+  ('key': 'value', 'key': 'value','key': 'value','key': 'value','key': 'value',):
+  ('list'),
+  ('list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list'):
+  ('list'),
+  ('list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list'):
+  ('key': 'value',),
+  ('key': 'value', 'key': 'value','key': 'value','key': 'value','key': 'value',):
+  1,
+);
+
+=====================================output=====================================
+$map: (
+  (
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value",
+  ):
+    (
+      "key": "value",
+    ),
+  (
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value",
+  ):
+    (
+      "list",
+    ),
+  (
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+  ):
+    (
+      "list",
+    ),
+  (
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+    "list",
+  ):
+    (
+      "key": "value",
+    ),
+  (
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value",
+    "key": "value",
+  ):
+    1,
+);
+
+================================================================================
+`;
+
+exports[`keys.scss - {"trailingComma":"none"} format 1`] = `
+====================================options=====================================
+parsers: ["scss"]
+printWidth: 80
+trailingComma: "none"
+                                                                                | printWidth
+=====================================input======================================
+$map: (
+  'string': 'hello world',
+  ('list'): 'hello world',
+  ('key': 'value'): 'hello world',
+  ('list', 'long long long long long long long long long long long long long list'): 'hello world',
+  ('key': 'value','long long long long long long long long long long long long long map': 'value',): 'hello world',
+);
+
+// #10000
+$map: (
+	('my list'): 'hello world',
+);
+
+=====================================output=====================================
+$map: (
+  "string": "hello world",
+  ("list"): "hello world",
+  ("key": "value"): "hello world",
+  (
+    "list",
+    "long long long long long long long long long long long long long list"
+  ):
+    "hello world",
+  (
+    "key": "value",
+    "long long long long long long long long long long long long long map":
+      "value"
+  ):
+    "hello world"
+);
+
+// #10000
+$map: (
+  ("my list"): "hello world"
+);
+
+================================================================================
+`;
+
+exports[`keys.scss format 1`] = `
+====================================options=====================================
+parsers: ["scss"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+$map: (
+  'string': 'hello world',
+  ('list'): 'hello world',
+  ('key': 'value'): 'hello world',
+  ('list', 'long long long long long long long long long long long long long list'): 'hello world',
+  ('key': 'value','long long long long long long long long long long long long long map': 'value',): 'hello world',
+);
+
+// #10000
+$map: (
+	('my list'): 'hello world',
+);
+
+=====================================output=====================================
+$map: (
+  "string": "hello world",
+  ("list"): "hello world",
+  ("key": "value"): "hello world",
+  (
+    "list",
+    "long long long long long long long long long long long long long list",
+  ):
+    "hello world",
+  (
+    "key": "value",
+    "long long long long long long long long long long long long long map":
+      "value",
+  ):
+    "hello world",
+);
+
+// #10000
+$map: (
+  ("my list"): "hello world",
+);
+
+================================================================================
+`;
diff --git a/tests/scss/map/jsfmt.spec.js b/tests/scss/map/jsfmt.spec.js
new file mode 100644
index 000000000..f2558a4a9
--- /dev/null
+++ b/tests/scss/map/jsfmt.spec.js
@@ -0,0 +1,2 @@
+run_spec(__dirname, ["scss"], { trailingComma: "none" });
+run_spec(__dirname, ["scss"]);
diff --git a/tests/scss/map/key-values.scss b/tests/scss/map/key-values.scss
new file mode 100644
index 000000000..2041334cd
--- /dev/null
+++ b/tests/scss/map/key-values.scss
@@ -0,0 +1,12 @@
+$map: (
+  ('key': 'value', 'key': 'value','key': 'value','key': 'value','key': 'value',):
+  ('key': 'value',),
+  ('key': 'value', 'key': 'value','key': 'value','key': 'value','key': 'value',):
+  ('list'),
+  ('list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list'):
+  ('list'),
+  ('list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list', 'list'):
+  ('key': 'value',),
+  ('key': 'value', 'key': 'value','key': 'value','key': 'value','key': 'value',):
+  1,
+);
diff --git a/tests/scss/map/keys.scss b/tests/scss/map/keys.scss
new file mode 100644
index 000000000..fe008a5d4
--- /dev/null
+++ b/tests/scss/map/keys.scss
@@ -0,0 +1,12 @@
+$map: (
+  'string': 'hello world',
+  ('list'): 'hello world',
+  ('key': 'value'): 'hello world',
+  ('list', 'long long long long long long long long long long long long long list'): 'hello world',
+  ('key': 'value','long long long long long long long long long long long long long map': 'value',): 'hello world',
+);
+
+// #10000
+$map: (
+	('my list'): 'hello world',
+);