diff --git a/packages/cutie-core/src/lib/expressionEvaluator/comparison.ts b/packages/cutie-core/src/lib/expressionEvaluator/comparison.ts
index 9974fd5..ebf97e7 100644
--- a/packages/cutie-core/src/lib/expressionEvaluator/comparison.ts
+++ b/packages/cutie-core/src/lib/expressionEvaluator/comparison.ts
@@ -3,7 +3,7 @@
  */
 
 import { getChildElements } from '../../utils/dom';
-import { deepEqual, deepEqualUnordered } from '../../utils/equality';
+import { deepEqual, deepEqualUnordered, stringEquals } from '../../utils/equality';
 import { compareMathExpressions, type MathComparisonMode } from './math';
 import type { SubEvaluate } from './types';
 
@@ -43,6 +43,20 @@ function getFormulaMode(itemDoc: Document, identifier: string): MathComparisonMo
   return null;
 }
 
+/**
+ * Check if a response declaration has base-type="string"
+ */
+function isStringBaseType(itemDoc: Document, identifier: string): boolean {
+  const declarations = itemDoc.getElementsByTagName('qti-response-declaration');
+  for (let i = 0; i < declarations.length; i++) {
+    const decl = declarations[i];
+    if (decl.getAttribute('identifier') === identifier) {
+      return decl.getAttribute('base-type') === 'string';
+    }
+  }
+  return false;
+}
+
 /**
  * Evaluate qti-lt (less than) element
  */
@@ -215,6 +229,12 @@ export function evaluateMatch(
           formulaMode
         );
       }
+
+      // String base-type responses use case-insensitive comparison by default
+      if (isStringBaseType(itemDoc, responseId) &&
+          typeof values[0] === 'string' && typeof values[1] === 'string') {
+        return stringEquals(values[0], values[1]);
+      }
     }
 
     return deepEqual(values[0], values[1]);
diff --git a/packages/cutie-core/src/lib/expressionEvaluator/string.ts b/packages/cutie-core/src/lib/expressionEvaluator/string.ts
index d2f41b2..ef0b29d 100644
--- a/packages/cutie-core/src/lib/expressionEvaluator/string.ts
+++ b/packages/cutie-core/src/lib/expressionEvaluator/string.ts
@@ -3,6 +3,7 @@
  */
 
 import { getChildElements } from '../../utils/dom';
+import { stringEquals, stringIncludes } from '../../utils/equality';
 import type { SubEvaluate } from './types';
 
 /**
@@ -22,9 +23,7 @@ export function evaluateSubstring(
   }
 
   if (values.length >= 2) {
-    const text = caseSensitive ? values[0] : values[0].toLowerCase();
-    const substring = caseSensitive ? values[1] : values[1].toLowerCase();
-    return text.includes(substring);
+    return stringIncludes(values[0], values[1], caseSensitive);
   }
 
   return false;
@@ -47,9 +46,7 @@ export function evaluateStringMatch(
   }
 
   if (values.length >= 2) {
-    const str1 = caseSensitive ? values[0] : values[0].toLowerCase();
-    const str2 = caseSensitive ? values[1] : values[1].toLowerCase();
-    return str1 === str2;
+    return stringEquals(values[0], values[1], caseSensitive);
   }
 
   return false;
diff --git a/packages/cutie-core/src/lib/responseProcessing.spec.ts b/packages/cutie-core/src/lib/responseProcessing.spec.ts
index 4a2c5ef..6bb626c 100644
--- a/packages/cutie-core/src/lib/responseProcessing.spec.ts
+++ b/packages/cutie-core/src/lib/responseProcessing.spec.ts
@@ -1573,7 +1573,7 @@ describe('Response Processing Operators and Expressions', () => {
       expect(newState.variables.SCORE).toBe(0);
     });
 
-    test('matches string values (case-sensitive)', () => {
+    test('qti-match uses case-insensitive comparison for string base-type', () => {
       const itemXml = `<?xml version="1.0" encoding="UTF-8"?>
 <qti-assessment-item xmlns="http://www.imsglobal.org/xsd/imsqtiasi_v3p0"
                      identifier="match-string">
@@ -1614,7 +1614,109 @@ describe('Response Processing Operators and Expressions', () => {
 
       const newState = processResponse(itemDoc, submission, currentState);
 
-      // Should not match due to case difference
+      // Should match case-insensitively for string base-type responses
+      expect(newState.variables.SCORE).toBe(1);
+    });
+
+    test('qti-match with qti-correct uses case-insensitive comparison for string base-type', () => {
+      const itemXml = `<?xml version="1.0" encoding="UTF-8"?>
+<qti-assessment-item xmlns="http://www.imsglobal.org/xsd/imsqtiasi_v3p0"
+                     identifier="match-string-correct">
+  <qti-response-declaration identifier="RESPONSE" cardinality="single" base-type="string">
+    <qti-correct-response>
+      <qti-value>wicked king</qti-value>
+    </qti-correct-response>
+  </qti-response-declaration>
+
+  <qti-outcome-declaration identifier="SCORE" cardinality="single" base-type="float">
+    <qti-default-value>
+      <qti-value>0</qti-value>
+    </qti-default-value>
+  </qti-outcome-declaration>
+
+  <qti-item-body>
+    <qti-text-entry-interaction response-identifier="RESPONSE"/>
+  </qti-item-body>
+
+  <qti-response-processing>
+    <qti-response-condition>
+      <qti-response-if>
+        <qti-match>
+          <qti-variable identifier="RESPONSE"/>
+          <qti-correct identifier="RESPONSE"/>
+        </qti-match>
+        <qti-set-outcome-value identifier="SCORE">
+          <qti-base-value base-type="float">1</qti-base-value>
+        </qti-set-outcome-value>
+      </qti-response-if>
+    </qti-response-condition>
+  </qti-response-processing>
+</qti-assessment-item>`;
+
+      const itemDoc = parser.parseFromString(itemXml, 'text/xml');
+      const currentState = {
+        variables: { SCORE: 0 },
+        completionStatus: 'not_attempted' as const,
+        score: null,
+      };
+      const submission = { RESPONSE: 'Wicked King' };
+
+      const newState = processResponse(itemDoc, submission, currentState);
+
+      // Should match case-insensitively for string base-type responses
+      expect(newState.variables.SCORE).toBe(1);
+    });
+
+    test('qti-match remains case-sensitive for identifier base-type', () => {
+      const itemXml = `<?xml version="1.0" encoding="UTF-8"?>
+<qti-assessment-item xmlns="http://www.imsglobal.org/xsd/imsqtiasi_v3p0"
+                     identifier="match-identifier">
+  <qti-response-declaration identifier="RESPONSE" cardinality="single" base-type="identifier">
+    <qti-correct-response>
+      <qti-value>ChoiceA</qti-value>
+    </qti-correct-response>
+  </qti-response-declaration>
+
+  <qti-outcome-declaration identifier="SCORE" cardinality="single" base-type="float">
+    <qti-default-value>
+      <qti-value>0</qti-value>
+    </qti-default-value>
+  </qti-outcome-declaration>
+
+  <qti-item-body>
+    <qti-choice-interaction response-identifier="RESPONSE" max-choices="1">
+      <qti-simple-choice identifier="ChoiceA">A</qti-simple-choice>
+      <qti-simple-choice identifier="ChoiceB">B</qti-simple-choice>
+    </qti-choice-interaction>
+  </qti-item-body>
+
+  <qti-response-processing>
+    <qti-response-condition>
+      <qti-response-if>
+        <qti-match>
+          <qti-variable identifier="RESPONSE"/>
+          <qti-correct identifier="RESPONSE"/>
+        </qti-match>
+        <qti-set-outcome-value identifier="SCORE">
+          <qti-base-value base-type="float">1</qti-base-value>
+        </qti-set-outcome-value>
+      </qti-response-if>
+    </qti-response-condition>
+  </qti-response-processing>
+</qti-assessment-item>`;
+
+      const itemDoc = parser.parseFromString(itemXml, 'text/xml');
+      const currentState = {
+        variables: { SCORE: 0 },
+        completionStatus: 'not_attempted' as const,
+        score: null,
+      };
+      // cspell:disable-next-line
+      const submission = { RESPONSE: 'choiceA' }; // wrong case
+
+      const newState = processResponse(itemDoc, submission, currentState);
+
+      // Should NOT match - identifier comparison is case-sensitive
       expect(newState.variables.SCORE).toBe(0);
     });
 
diff --git a/packages/cutie-core/src/lib/responseProcessing.ts b/packages/cutie-core/src/lib/responseProcessing.ts
index 8926303..1da4275 100644
--- a/packages/cutie-core/src/lib/responseProcessing.ts
+++ b/packages/cutie-core/src/lib/responseProcessing.ts
@@ -1,6 +1,6 @@
 import { AttemptState, ResponseData } from '../types';
 import { getChildElements, getFirstChildElement } from '../utils/dom';
-import { deepEqual, deepEqualUnordered } from '../utils/equality';
+import { deepEqual, deepEqualUnordered, stringEquals } from '../utils/equality';
 import { parseResponseValue } from '../utils/typeParser';
 import {
   evaluateExpression as evaluateExpressionShared,
@@ -407,9 +407,7 @@ function getMappedValue(value: unknown, mapping: ResponseMapping): number {
   const key = String(value);
 
   for (const entry of mapping.entries) {
-    const matches = entry.caseSensitive
-      ? key === entry.mapKey
-      : key.toLowerCase() === entry.mapKey.toLowerCase();
+    const matches = stringEquals(key, entry.mapKey, entry.caseSensitive);
 
     if (matches) {
       return entry.mappedValue;
diff --git a/packages/cutie-core/src/utils/equality.ts b/packages/cutie-core/src/utils/equality.ts
index 25ae1e0..2ef3363 100644
--- a/packages/cutie-core/src/utils/equality.ts
+++ b/packages/cutie-core/src/utils/equality.ts
@@ -1,3 +1,19 @@
+/**
+ * Case-aware string equality. Defaults to case-insensitive.
+ */
+export function stringEquals(a: string, b: string, caseSensitive = false): boolean {
+  return caseSensitive ? a === b : a.toLowerCase() === b.toLowerCase();
+}
+
+/**
+ * Case-aware substring check. Defaults to case-insensitive.
+ */
+export function stringIncludes(haystack: string, needle: string, caseSensitive = false): boolean {
+  return caseSensitive
+    ? haystack.includes(needle)
+    : haystack.toLowerCase().includes(needle.toLowerCase());
+}
+
 /**
  * Deep equality check for comparing values
  */