diff --git a/crates/engine/src/cmd/insert.rs b/crates/engine/src/cmd/insert.rs
index d878e4469..9f044613d 100644
--- a/crates/engine/src/cmd/insert.rs
+++ b/crates/engine/src/cmd/insert.rs
@@ -466,10 +466,11 @@ fn table_style(s: &mut Session, p: &Json) -> Result<Json> {
 }
 
 /// Table names follow the Microsoft name rules, as the xlsx writer does: letters, digits, `_` and `.`,
-/// starting with a letter, `_` or `\`. Anything else (a hyphen, say) would read as an operator inside a
-/// structured reference, and the writer would rename the table on save.
+/// starting with a letter, `_` or `\`, and at most 255 characters. Anything else (a hyphen, say) would
+/// read as an operator inside a structured reference, and the writer would rename the table on save.
 fn valid_table_name(name: &str) -> bool {
-    name.starts_with(|c: char| c.is_alphabetic() || c == '_' || c == '\\')
+    name.chars().count() <= 255
+        && name.starts_with(|c: char| c.is_alphabetic() || c == '_' || c == '\\')
         && CellRef::parse(name).is_none()
         && name.chars().enumerate().all(|(i, c)| c.is_alphanumeric() || c == '_' || c == '.' || (i == 0 && c == '\\'))
 }
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 513366848..db6ad1e2a 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -1222,6 +1222,26 @@ fn table_rename_keeps_a_defined_name_with_the_same_name() {
     assert_eq!((v(&s, "E1"), v(&s, "F1")), (Value::Number(100.0), Value::Number(7.0)));
 }
 
+#[test]
+fn table_names_are_limited_to_255_characters() {
+    let mut s = s();
+    s.execute("range.setValues", json!({"range": "A1", "values": [["Qty"], [7]]})).unwrap();
+    s.execute("insert.table", json!({"range": "A1:A2", "header": true, "name": "Original"})).unwrap();
+
+    let name_255 = "ع".repeat(255);
+    s.execute("table.rename", json!({"table": "Original", "name": name_255})).unwrap();
+    assert!(s.doc().unwrap().wb.table(&"ع".repeat(255)).is_some());
+
+    let name_256 = "ع".repeat(256);
+    let error = s.execute("table.rename", json!({"table": &"ع".repeat(255), "name": name_256})).unwrap_err();
+    assert!(error.to_string().contains("not valid"), "{error}");
+    assert!(s.doc().unwrap().wb.table(&"ع".repeat(255)).is_some());
+
+    let name_200 = "ع".repeat(200);
+    s.execute("table.rename", json!({"table": &"ع".repeat(255), "name": name_200})).unwrap();
+    assert!(s.doc().unwrap().wb.table(&"ع".repeat(200)).is_some());
+}
+
 #[test]
 fn slicer_filters_table() {
     let mut s = s();
diff --git a/docs/localization-parity.md b/docs/localization-parity.md
index 6885a595a..a05ad69f1 100644
--- a/docs/localization-parity.md
+++ b/docs/localization-parity.md
@@ -1,6 +1,7 @@
 # Localization parity
 
 > **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-19 · **Change:** minor (defined-name length limit counts characters, so long Arabic names are accepted) · **Target:** Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-19 · **Change:** minor (Table names are limited to 255 characters) · **Target:** Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4
 
 Per-language status against Excel, which ships its UI in dozens of languages (Windows language
 packs cover 100+), with localized function names, argument separators, number and date formats,
@@ -82,6 +83,7 @@ language (none so far) and of localized function names.
 | Date | Change | Summary |
 |---|---|---|
 | 2026-10-19 | minor | Defined-name length counts characters, not bytes: Arabic names up to 255 letters are accepted, and Create from Selection keeps long Arabic headers |
+| 2026-10-19 | minor | Table names are limited to 255 Unicode characters |
 | 2026-10-12 | minor | Format Cells looks up its tabs, labels, options and note through `Language::tr` (Fill tab keyed `Format Cells\|Fill`); dialog titles and OK/Cancel too. Labels already in a table (Number, Currency, Fill…) show translated; the rest fall back to English until the tables add them |
 | 2026-10-12 | minor | Brazilian Portuguese catalog (`i18n/pt.rs`) grows from 377 to 923 entries: every key the other catalogs translate, including the dialog strings #669 starts looking up (~42%) |
 | 2026-10-11 | minor | German ribbon catalog (`i18n/de.rs`, 266 labels, ~12%); `de` locale tags (de-DE, de-AT, de-CH…) resolve to German. PR #163 (localized German formulas/numbers) still open |