diff --git a/src/utils/get-sorted-nodes-by-import-order.ts b/src/utils/get-sorted-nodes-by-import-order.ts
index dc0f8e3..9c04215 100644
--- a/src/utils/get-sorted-nodes-by-import-order.ts
+++ b/src/utils/get-sorted-nodes-by-import-order.ts
@@ -56,11 +56,18 @@ export const getSortedNodesByImportOrder: GetSortedNodesByImportOrder = (
 
     // Assign import nodes into import order groups
     for (const node of originalNodes) {
-        const matchedGroup = getImportNodesMatchedGroup(
+        const matchedGroupName = getImportNodesMatchedGroup(
             node,
             sanitizedImportOrder,
         );
-        importOrderGroups[matchedGroup].push(node);
+        const matchedGroup = importOrderGroups[matchedGroupName];
+        if (matchedGroup) {
+            matchedGroup.push(node);
+        } else {
+            throw new Error(
+                `Could not find a matching group in importOrder for: "${node.source.value}" on line ${node.source.loc?.start.line}.${node.importKind === 'type' ? ' Did you forget to include "<TYPES>"?' : ''}`,
+            );
+        }
     }
 
     for (const group of importOrder) {
diff --git a/test-setup/run_spec.ts b/test-setup/run_spec.ts
index 48a0e85..7a277d8 100644
--- a/test-setup/run_spec.ts
+++ b/test-setup/run_spec.ts
@@ -64,6 +64,47 @@ export async function run_spec(dirname, parsers, options) {
     }
 }
 
+export async function expectError(
+    dirname: string,
+    parser: string,
+    expectedError: string | Error | RegExp,
+    options,
+) {
+    options = Object.assign(
+        {
+            plugins: options.plugins ?? [plugin],
+            tabWidth: 4,
+        },
+        options,
+    );
+
+    /* instabul ignore if */
+    if (!parser) {
+        throw new Error(`No parser was specified for ${dirname}`);
+    }
+
+    for (const filename of fs.readdirSync(dirname)) {
+        const path = dirname + '/' + filename;
+        if (
+            extname(filename) !== '.snap' &&
+            fs.lstatSync(path).isFile() &&
+            filename[0] !== '.' &&
+            filename !== 'ppsi.spec.ts'
+        ) {
+            const source = read(path).replace(/\r\n/g, '\n');
+
+            const mergedOptions = Object.assign({}, options, {
+                parser,
+            });
+            test(`${filename} - verify-error`, async () => {
+                expect(() =>
+                    prettyprint(source, path, mergedOptions),
+                ).rejects.toThrowError(expectedError);
+            });
+        }
+    }
+}
+
 async function prettyprint(src, filename, options) {
     return await format(
         src,
diff --git a/tests/ImportOrderMissing/importOrderMissing.ts b/tests/ImportOrderMissing/importOrderMissing.ts
new file mode 100644
index 0000000..8afc9b4
--- /dev/null
+++ b/tests/ImportOrderMissing/importOrderMissing.ts
@@ -0,0 +1,4 @@
+import Foo from "./bar";
+import type {Justify} from "#utils"
+import type {React} from "React";
+import type {Internal} from "./types.ts";
diff --git a/tests/ImportOrderMissing/ppsi.spec.ts b/tests/ImportOrderMissing/ppsi.spec.ts
new file mode 100644
index 0000000..6e7058d
--- /dev/null
+++ b/tests/ImportOrderMissing/ppsi.spec.ts
@@ -0,0 +1,11 @@
+import {expectError} from '../../test-setup/run_spec';
+
+expectError(
+    __dirname,
+    "typescript",
+    /Could not find a matching group in importOrder for: \"React\" on line 3. Did you forget to include \"<TYPES>\"\?$/,
+    {
+        importOrder: ['^[./]', '<TYPES>^#utils$', '<TYPES>[.]'],
+        importOrderParserPlugins: ['typescript'],
+    }
+);