diff --git a/langextract/visualization.py b/langextract/visualization.py
index 725757cb..b7e7cd06 100644
--- a/langextract/visualization.py
+++ b/langextract/visualization.py
@@ -175,6 +175,8 @@ def _is_jupyter() -> bool:
     .lx-gif-optimized .lx-current-highlight { text-decoration-thickness: 4px; }
     </style>""")
 
+_HTML_CHARSET_META = '<meta charset="UTF-8">\n'
+
 
 def _assign_colors(extractions: list[data.Extraction]) -> dict[str, str]:
   """Assigns a background colour to each extraction class.
@@ -600,7 +602,7 @@ def visualize(
         '<div class="lx-animated-wrapper"><p>No valid extractions to'
         ' animate.</p></div>'
     )
-    full_html = _VISUALIZATION_CSS + empty_html
+    full_html = _HTML_CHARSET_META + _VISUALIZATION_CSS + empty_html
     if HTML is not None and _is_jupyter():
       return HTML(full_html)
     return full_html
@@ -615,7 +617,7 @@ def visualize(
       show_legend,
   )
 
-  full_html = _VISUALIZATION_CSS + visualization_html
+  full_html = _HTML_CHARSET_META + _VISUALIZATION_CSS + visualization_html
 
   # Apply GIF optimizations if requested
   if gif_optimized:
diff --git a/tests/visualization_test.py b/tests/visualization_test.py
index 43f42759..6fb48268 100644
--- a/tests/visualization_test.py
+++ b/tests/visualization_test.py
@@ -22,6 +22,7 @@
 from langextract.core import data
 
 _PALETTE = visualization._PALETTE
+_HTML_CHARSET_META = visualization._HTML_CHARSET_META
 _VISUALIZATION_CSS = visualization._VISUALIZATION_CSS
 
 
@@ -134,6 +135,7 @@ def test_visualize_basic_document_renders_correctly(self):
 
     actual_html = visualization.visualize(doc)
 
+    self.assertTrue(actual_html.startswith(_HTML_CHARSET_META))
     # Verify expected components appear in output
     for component in expected_components:
       self.assertIn(component, actual_html)
@@ -149,7 +151,7 @@ def test_visualize_no_extractions_renders_text_and_empty_legend(self):
         " animate.</p></div>"
     )
     css_html = _VISUALIZATION_CSS
-    expected_html = css_html + body_html
+    expected_html = _HTML_CHARSET_META + css_html + body_html
 
     actual_html = visualization.visualize(doc)