diff --git a/src/diacritics.ts b/src/diacritics.ts
index a1a7e2a..067e0b8 100644
--- a/src/diacritics.ts
+++ b/src/diacritics.ts
@@ -92,7 +92,8 @@ export const diacritics: Diacritics[] = [
   { letter: 'p', diacritics: /[\u0070\u24DF\uFF50\u1E55\u1E57\u01A5\u1D7D\uA751\uA753\uA755]/g },
   { letter: 'q', diacritics: /[\u0071\u24E0\uFF51\u024B\uA757\uA759]/g },
   { letter: 'r', diacritics: /[\u0072\u24E1\uFF52\u0155\u1E59\u0159\u0211\u0213\u1E5B\u1E5D\u0157\u1E5F\u024D\u027D\uA75B\uA7A7\uA783]/g },
-  { letter: 's', diacritics: /[\u0073\u24E2\uFF53\u00DF\u015B\u1E65\u015D\u1E61\u0161\u1E67\u1E63\u1E69\u0219\u015F\u023F\uA7A9\uA785\u1E9B]/g },
+  { letter: 's', diacritics: /[\u0073\u24E2\uFF53\u015B\u1E65\u015D\u1E61\u0161\u1E67\u1E63\u1E69\u0219\u015F\u023F\uA7A9\uA785\u1E9B]/g },
+  { letter: 'ss', diacritics: /\u00DF/g },
   { letter: 't', diacritics: /[\u0074\u24E3\uFF54\u1E6B\u1E97\u0165\u1E6D\u021B\u0163\u1E71\u1E6F\u0167\u01AD\u0288\u2C66\uA787]/g },
   { letter: 'th', diacritics: /\u00FE/g },
   { letter: 'tz', diacritics: /\uA729/g },
diff --git a/src/tests/normalize-sync.test.ts b/src/tests/normalize-sync.test.ts
index 575bc4f..d5b62ce 100644
--- a/src/tests/normalize-sync.test.ts
+++ b/src/tests/normalize-sync.test.ts
@@ -16,7 +16,7 @@ describe(normalizeSync.name, () => {
     // non-accented characters (Latin-1 Supplement)
     { input: `tromsø`, output: 'tromso' },
     { input: `\u00d8`, output: 'O' },
-    { input: `Muße`, output: 'Muse' },
+    { input: `Muße`, output: 'Musse' },
 
     // repeated characters
     { input: `éééé`, output: 'eeee' },
diff --git a/src/tests/normalize.test.ts b/src/tests/normalize.test.ts
index 6b865c3..1f56c2c 100644
--- a/src/tests/normalize.test.ts
+++ b/src/tests/normalize.test.ts
@@ -16,7 +16,7 @@ describe(normalize.name, () => {
     // non-accented characters (Latin-1 Supplement)
     { input: `tromsø`, output: 'tromso' },
     { input: `\u00d8`, output: 'O' },
-    { input: `Muße`, output: 'Muse' },
+    { input: `Muße`, output: 'Musse' },
 
     // repeated characters
     { input: `éééé`, output: 'eeee' },