diff --git a/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/InvalidLoopArguments.spec.ts b/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/InvalidLoopArguments.spec.ts
index 29bacff93..150048d3d 100644
--- a/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/InvalidLoopArguments.spec.ts
+++ b/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/InvalidLoopArguments.spec.ts
@@ -1,5 +1,5 @@
 import { expect, describe, it } from 'vitest';
-import { applyFix, runLiquidCheck } from '../../../test';
+import { applyFix, autofix, runLiquidCheck } from '../../../test';
 import { LiquidHTMLSyntaxError } from '../index';
 
 describe('detectInvalidLoopArguments', async () => {
@@ -17,6 +17,16 @@ describe('detectInvalidLoopArguments', async () => {
     }
   });
 
+  it('does not flag or rewrite a quoted lookup key containing spaces', async () => {
+    const sourceCode =
+      "{%- for value in product.options_by_name['hello world'].values -%}{{ value }}{%- endfor -%}";
+    const offenses = await testCheck(sourceCode);
+
+    expect(offenses).to.have.length(0);
+    const fixed = await autofix({ 'file.liquid': sourceCode }, offenses);
+    expect(fixed['file.liquid']).to.equal(sourceCode);
+  });
+
   it('should report when invalid args are found', async () => {
     const testCases = [
       [
diff --git a/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/utils.spec.ts b/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/utils.spec.ts
index 2f6d6706c..56c99e572 100644
--- a/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/utils.spec.ts
+++ b/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/utils.spec.ts
@@ -57,6 +57,17 @@ describe('getFragmentsInMarkup', () => {
     expect(values).toContainEqual(expect.objectContaining({ value: '( 1 .. 10 )' }));
     expect(values).toContainEqual(expect.objectContaining({ value: '( 1 ... 10 )' }));
   });
+
+  it('should keep spaces inside quoted bracket lookups within one fragment', () => {
+    const markup = "value in product.options_by_name['hello world'].values";
+    const values = getFragmentsInMarkup(markup);
+
+    expect(values.map(({ value }) => value)).toEqual([
+      'value',
+      'in',
+      "product.options_by_name['hello world'].values",
+    ]);
+  });
 });
 
 describe('fragmentKeyValuePair', () => {
diff --git a/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/utils.ts b/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/utils.ts
index 8ae1976fb..63878acc3 100644
--- a/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/utils.ts
+++ b/packages/theme-check-common/src/checks/liquid-html-syntax-error/checks/utils.ts
@@ -20,6 +20,12 @@ const REGULAR_TOKEN = `[^\\s,]+`; // tokens separated by commas or spaces
 // Quoted strings pattern (combination of double and single quoted)
 const QUOTED_STRING = `(${DOUBLE_QUOTED_STRING}|${SINGLE_QUOTED_STRING})`;
 
+// Keep a lookup such as `product.options_by_name['hello world'].values`
+// together when splitting markup into space-separated fragments.
+const BRACKET_LOOKUP = `\\[(?:${QUOTED_STRING}|[^\\]]+)\\]`;
+const LOOKUP_ID = `[a-zA-Z_][\\w-]*\\??`;
+const VARIABLE_LOOKUP = `(?:${LOOKUP_ID}(?:\\.${LOOKUP_ID})*|${BRACKET_LOOKUP})(?:\\.${LOOKUP_ID}|${BRACKET_LOOKUP})*`;
+
 // Value pattern for key-value pairs (can be quoted, parenthesized, or regular token)
 const VALUE_PATTERN = `(${QUOTED_STRING}|${RANGE_MARKUP_REGEX}|${REGULAR_TOKEN})`;
 
@@ -27,7 +33,7 @@ const VALUE_PATTERN = `(${QUOTED_STRING}|${RANGE_MARKUP_REGEX}|${REGULAR_TOKEN})
 const KEY_VALUE_PAIR = `(\\S+):\\s*${VALUE_PATTERN}`;
 
 const MARKUP_FRAGMENTS_PATTERN = new RegExp(
-  `${QUOTED_STRING}|${RANGE_MARKUP_REGEX}|${KEY_VALUE_PAIR}|${REGULAR_TOKEN}`,
+  `${QUOTED_STRING}|${RANGE_MARKUP_REGEX}|${KEY_VALUE_PAIR}|${VARIABLE_LOOKUP}|${REGULAR_TOKEN}`,
   'g',
 );