diff --git a/TypeScriptReact.YAML-tmLanguage b/TypeScriptReact.YAML-tmLanguage
index f2d203de..50dfc255 100644
--- a/TypeScriptReact.YAML-tmLanguage
+++ b/TypeScriptReact.YAML-tmLanguage
@@ -12,7 +12,7 @@ variables:
   # because tsx cannot have cast expression, we can say <T extends starts the type parameter of arrow
   typeparamertStartOfArrow: |-
     (
-      [<]\s*{{identifier}}\s+extends\s*[^=>]                                                              # < typeparam extends
+      [<]\s*(const\s+)?{{identifier}}\s+extends\s*[^=>]                                                   # < typeparam extends (optional const modifier from TS 5.0)
     ) |
   #possiblyMultilineArrowExpressionBeforeEndOfLine: ({{typeParameters}})?\(
   possiblyMultilineArrow: ((<\s*$)|({{possiblyMultilineArrowWithoutTypeParameters}}))  # during lookup treat ( followed by line end as arrow
@@ -80,7 +80,7 @@ repository:
     begin: |-
       (?x)
         {{jsxLookBehindInExpression}}
-        (?!<\s*[_$[:alpha:]][_$[:alnum:]]*((\s+extends\s+[^=>])|,)) # look ahead is not type parameter of arrow
+        (?!<\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*((\s+extends\s+[^=>])|,)) # look ahead is not type parameter of arrow (optional const modifier from TS 5.0)
         {{jsxTagStartLookahead}}
     end: (?!{{jsxTagStart}})
     patterns:
diff --git a/TypeScriptReact.tmLanguage b/TypeScriptReact.tmLanguage
index a7aec5da..0c23f2ed 100644
--- a/TypeScriptReact.tmLanguage
+++ b/TypeScriptReact.tmLanguage
@@ -761,7 +761,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -804,7 +804,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -924,7 +924,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -967,7 +967,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -1590,7 +1590,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -1633,7 +1633,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -2057,7 +2057,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -2100,7 +2100,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -2678,7 +2678,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -4672,7 +4672,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -5350,7 +5350,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -5393,7 +5393,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -6686,7 +6686,7 @@
   )
 ) |
 (
-  [&lt;]\s*[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                              # &lt; typeparam extends
+  [&lt;]\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*\s+extends\s*[^=&gt;]                                                   # &lt; typeparam extends (optional const modifier from TS 5.0)
 ) |
 # arrow function possible to detect only with =&gt; on same line
 (
@@ -9918,7 +9918,7 @@
         <key>begin</key>
         <string>(?x)
   (?&lt;!\+\+|--)(?&lt;=[({\[,?=&gt;:*]|&amp;&amp;|\|\||\?|\*\/|^await|[^\._$[:alnum:]]await|^return|[^\._$[:alnum:]]return|^default|[^\._$[:alnum:]]default|^yield|[^\._$[:alnum:]]yield|^)\s*
-  (?!&lt;\s*[_$[:alpha:]][_$[:alnum:]]*((\s+extends\s+[^=&gt;])|,)) # look ahead is not type parameter of arrow
+  (?!&lt;\s*(const\s+)?[_$[:alpha:]][_$[:alnum:]]*((\s+extends\s+[^=&gt;])|,)) # look ahead is not type parameter of arrow (optional const modifier from TS 5.0)
   (?=(&lt;)\s*(?:([_$[:alpha:]][-_$[:alnum:].]*)(?&lt;!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$[:alpha:]][-_$[:alnum:].]*))(?&lt;!\.|-))(?=((&lt;\s*)|(\s+))(?!\?)|\/?&gt;))</string>
         <key>end</key>
         <string>(?!(&lt;)\s*(?:([_$[:alpha:]][-_$[:alnum:].]*)(?&lt;!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$[:alpha:]][-_$[:alnum:].]*))(?&lt;!\.|-))(?=((&lt;\s*)|(\s+))(?!\?)|\/?&gt;))</string>
diff --git a/tests/baselines/constTypeParameter.baseline.txt b/tests/baselines/constTypeParameter.baseline.txt
index 48386d73..d4ac7661 100644
--- a/tests/baselines/constTypeParameter.baseline.txt
+++ b/tests/baselines/constTypeParameter.baseline.txt
@@ -1,6 +1,5 @@
 original file
 -----------------------------------
-// @onlyOwnGrammar - this has type parameters that would be jsx in tsx files
 declare function f1<const T>(x: T): T;
 declare function f2<const T, U>(x: T | undefined): T;
 declare function f3<const T>(x: T): T[];
@@ -12,7 +11,6 @@ class C1<const T> {
     foo<const U>(x: U) { return x; }
 }
 const C2 = class <const T> {}
-const fx1 = <const T>(x: T) => x;
 const fx2 = <const T,>(x: T) => x;
 interface I1<const T> { x: T }  // Error
 interface I2 {
@@ -28,11 +26,6 @@ function set<T, const P extends readonly string[]>(obj: T, path: P, value: GetPa
 
 Grammar: TypeScript.tmLanguage
 -----------------------------------
->// @onlyOwnGrammar - this has type parameters that would be jsx in tsx files
- ^^
- source.ts comment.line.double-slash.ts punctuation.definition.comment.ts
-   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   source.ts comment.line.double-slash.ts
 >declare function f1<const T>(x: T): T;
  ^^^^^^^
  source.ts meta.function.ts storage.modifier.ts
@@ -476,51 +469,6 @@ Grammar: TypeScript.tmLanguage
                             source.ts meta.var.expr.ts meta.class.ts punctuation.definition.block.ts
                              ^
                              source.ts meta.var.expr.ts meta.class.ts punctuation.definition.block.ts
->const fx1 = <const T>(x: T) => x;
- ^^^^^
- source.ts meta.var.expr.ts storage.type.ts
-      ^
-      source.ts meta.var.expr.ts
-       ^^^
-       source.ts meta.var.expr.ts meta.var-single-variable.expr.ts meta.definition.variable.ts variable.other.constant.ts entity.name.function.ts
-          ^
-          source.ts meta.var.expr.ts meta.var-single-variable.expr.ts
-           ^
-           source.ts meta.var.expr.ts keyword.operator.assignment.ts
-            ^
-            source.ts meta.var.expr.ts meta.arrow.ts
-             ^
-             source.ts meta.var.expr.ts meta.arrow.ts meta.type.parameters.ts punctuation.definition.typeparameters.begin.ts
-              ^^^^^
-              source.ts meta.var.expr.ts meta.arrow.ts meta.type.parameters.ts storage.modifier.ts
-                   ^
-                   source.ts meta.var.expr.ts meta.arrow.ts meta.type.parameters.ts
-                    ^
-                    source.ts meta.var.expr.ts meta.arrow.ts meta.type.parameters.ts entity.name.type.ts
-                     ^
-                     source.ts meta.var.expr.ts meta.arrow.ts meta.type.parameters.ts punctuation.definition.typeparameters.end.ts
-                      ^
-                      source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts punctuation.definition.parameters.begin.ts
-                       ^
-                       source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts variable.parameter.ts
-                        ^
-                        source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts meta.type.annotation.ts keyword.operator.type.annotation.ts
-                         ^
-                         source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts meta.type.annotation.ts
-                          ^
-                          source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts meta.type.annotation.ts entity.name.type.ts
-                           ^
-                           source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts punctuation.definition.parameters.end.ts
-                            ^
-                            source.ts meta.var.expr.ts meta.arrow.ts
-                             ^^
-                             source.ts meta.var.expr.ts meta.arrow.ts storage.type.function.arrow.ts
-                               ^
-                               source.ts meta.var.expr.ts meta.arrow.ts
-                                ^
-                                source.ts meta.var.expr.ts variable.other.readwrite.ts
-                                 ^
-                                 source.ts punctuation.terminator.statement.ts
 >const fx2 = <const T,>(x: T) => x;
  ^^^^^
  source.ts meta.var.expr.ts storage.type.ts
diff --git a/tests/baselines/constTypeParameterJsxOnly.baseline.txt b/tests/baselines/constTypeParameterJsxOnly.baseline.txt
new file mode 100644
index 00000000..01c2b730
--- /dev/null
+++ b/tests/baselines/constTypeParameterJsxOnly.baseline.txt
@@ -0,0 +1,62 @@
+original file
+-----------------------------------
+// @onlyOwnGrammar - bare `<const T>(x: T) => x` in expression position is unresolvably jsx-ambiguous in tsx
+const fx1 = <const T>(x: T) => x;
+
+-----------------------------------
+
+Grammar: TypeScript.tmLanguage
+-----------------------------------
+>// @onlyOwnGrammar - bare `<const T>(x: T) => x` in expression position is unresolvably jsx-ambiguous in tsx
+ ^^
+ source.ts comment.line.double-slash.ts punctuation.definition.comment.ts
+   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   source.ts comment.line.double-slash.ts
+>const fx1 = <const T>(x: T) => x;
+ ^^^^^
+ source.ts meta.var.expr.ts storage.type.ts
+      ^
+      source.ts meta.var.expr.ts
+       ^^^
+       source.ts meta.var.expr.ts meta.var-single-variable.expr.ts meta.definition.variable.ts variable.other.constant.ts entity.name.function.ts
+          ^
+          source.ts meta.var.expr.ts meta.var-single-variable.expr.ts
+           ^
+           source.ts meta.var.expr.ts keyword.operator.assignment.ts
+            ^
+            source.ts meta.var.expr.ts meta.arrow.ts
+             ^
+             source.ts meta.var.expr.ts meta.arrow.ts meta.type.parameters.ts punctuation.definition.typeparameters.begin.ts
+              ^^^^^
+              source.ts meta.var.expr.ts meta.arrow.ts meta.type.parameters.ts storage.modifier.ts
+                   ^
+                   source.ts meta.var.expr.ts meta.arrow.ts meta.type.parameters.ts
+                    ^
+                    source.ts meta.var.expr.ts meta.arrow.ts meta.type.parameters.ts entity.name.type.ts
+                     ^
+                     source.ts meta.var.expr.ts meta.arrow.ts meta.type.parameters.ts punctuation.definition.typeparameters.end.ts
+                      ^
+                      source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts punctuation.definition.parameters.begin.ts
+                       ^
+                       source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts variable.parameter.ts
+                        ^
+                        source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts meta.type.annotation.ts keyword.operator.type.annotation.ts
+                         ^
+                         source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts meta.type.annotation.ts
+                          ^
+                          source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts meta.type.annotation.ts entity.name.type.ts
+                           ^
+                           source.ts meta.var.expr.ts meta.arrow.ts meta.parameters.ts punctuation.definition.parameters.end.ts
+                            ^
+                            source.ts meta.var.expr.ts meta.arrow.ts
+                             ^^
+                             source.ts meta.var.expr.ts meta.arrow.ts storage.type.function.arrow.ts
+                               ^
+                               source.ts meta.var.expr.ts meta.arrow.ts
+                                ^
+                                source.ts meta.var.expr.ts variable.other.readwrite.ts
+                                 ^
+                                 source.ts punctuation.terminator.statement.ts
+>
+ ^
+ source.ts
\ No newline at end of file
diff --git a/tests/cases/constTypeParameter.ts b/tests/cases/constTypeParameter.ts
index cc9290a5..fe8363e6 100644
--- a/tests/cases/constTypeParameter.ts
+++ b/tests/cases/constTypeParameter.ts
@@ -1,4 +1,3 @@
-// @onlyOwnGrammar - this has type parameters that would be jsx in tsx files
 declare function f1<const T>(x: T): T;
 declare function f2<const T, U>(x: T | undefined): T;
 declare function f3<const T>(x: T): T[];
@@ -10,7 +9,6 @@ class C1<const T> {
     foo<const U>(x: U) { return x; }
 }
 const C2 = class <const T> {}
-const fx1 = <const T>(x: T) => x;
 const fx2 = <const T,>(x: T) => x;
 interface I1<const T> { x: T }  // Error
 interface I2 {
diff --git a/tests/cases/constTypeParameterJsxOnly.ts b/tests/cases/constTypeParameterJsxOnly.ts
new file mode 100644
index 00000000..4c09afcc
--- /dev/null
+++ b/tests/cases/constTypeParameterJsxOnly.ts
@@ -0,0 +1,2 @@
+// @onlyOwnGrammar - bare `<const T>(x: T) => x` in expression position is unresolvably jsx-ambiguous in tsx
+const fx1 = <const T>(x: T) => x;