diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 631ded027b8..c6bf689518d 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -40728,6 +40728,7 @@ namespace ts {
         }
 
         function checkGrammarJsxElement(node: JsxOpeningLikeElement) {
+            checkGrammarJsxName(node.tagName);
             checkGrammarTypeArguments(node, node.typeArguments);
             const seen = new Map<__String, boolean>();
 
@@ -40750,6 +40751,29 @@ namespace ts {
             }
         }
 
+        function checkGrammarJsxName(node: JsxTagNameExpression) {
+            if (isPropertyAccessExpression(node)) {
+                let propName: JsxTagNameExpression = node;
+                do {
+                    const check = checkGrammarJsxNestedIdentifier(propName.name);
+                    if (check) {
+                        return check;
+                    }
+                    propName = propName.expression;
+                } while (isPropertyAccessExpression(propName));
+                const check = checkGrammarJsxNestedIdentifier(propName);
+                if (check) {
+                    return check;
+                }
+            }
+
+            function checkGrammarJsxNestedIdentifier(name: MemberName | ThisExpression) {
+                if (isIdentifier(name) && idText(name).indexOf(":") !== -1) {
+                    return grammarErrorOnNode(name, Diagnostics.JSX_property_access_expressions_cannot_include_JSX_namespace_names);
+                }
+            }
+        }
+
         function checkGrammarJsxExpression(node: JsxExpression) {
             if (node.expression && isCommaSequence(node.expression)) {
                 return grammarErrorOnNode(node.expression, Diagnostics.JSX_expressions_may_not_use_the_comma_operator_Did_you_mean_to_write_an_array);
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 789f7d167d7..ae8fe1998fb 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -2674,6 +2674,10 @@
         "category": "Error",
         "code": 2632
     },
+    "JSX property access expressions cannot include JSX namespace names": {
+        "category": "Error",
+        "code": 2633
+    },
 
     "Cannot augment module '{0}' with value exports because it resolves to a non-module entity.": {
         "category": "Error",
diff --git a/src/compiler/scanner.ts b/src/compiler/scanner.ts
index c42186ea7f6..ca3290b25e1 100644
--- a/src/compiler/scanner.ts
+++ b/src/compiler/scanner.ts
@@ -2335,6 +2335,7 @@ namespace ts {
                         tokenValue += ":";
                         pos++;
                         namespaceSeparator = true;
+                        token = SyntaxKind.Identifier; // swap from keyword kind to identifier kind
                         continue;
                     }
                     const oldPos = pos;
diff --git a/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.errors.txt b/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.errors.txt
new file mode 100644
index 00000000000..d758a3ed0c9
--- /dev/null
+++ b/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.errors.txt
@@ -0,0 +1,25 @@
+tests/cases/conformance/jsx/checkJsxNamespaceNamesQuestionableForms.tsx(12,2): error TS2304: Cannot find name 'b:c'.
+tests/cases/conformance/jsx/checkJsxNamespaceNamesQuestionableForms.tsx(12,2): error TS2633: JSX property access expressions cannot include JSX namespace names
+tests/cases/conformance/jsx/checkJsxNamespaceNamesQuestionableForms.tsx(12,10): error TS2304: Cannot find name 'b:c'.
+
+
+==== tests/cases/conformance/jsx/checkJsxNamespaceNamesQuestionableForms.tsx (3 errors) ====
+    declare namespace JSX {
+        interface IntrinsicElements {
+            'this:b': any;
+            'b:c': {
+                x: any
+            };
+            'a:b': any;
+        }
+    }
+    
+    <a:b></a:b>;
+    <b:c.x></b:c.x>;
+     ~~~
+!!! error TS2304: Cannot find name 'b:c'.
+     ~~~
+!!! error TS2633: JSX property access expressions cannot include JSX namespace names
+             ~~~
+!!! error TS2304: Cannot find name 'b:c'.
+    <this:b></this:b>;
\ No newline at end of file
diff --git a/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.js b/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.js
new file mode 100644
index 00000000000..6189a8f9d78
--- /dev/null
+++ b/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.js
@@ -0,0 +1,19 @@
+//// [checkJsxNamespaceNamesQuestionableForms.tsx]
+declare namespace JSX {
+    interface IntrinsicElements {
+        'this:b': any;
+        'b:c': {
+            x: any
+        };
+        'a:b': any;
+    }
+}
+
+<a:b></a:b>;
+<b:c.x></b:c.x>;
+<this:b></this:b>;
+
+//// [checkJsxNamespaceNamesQuestionableForms.jsx]
+<a:b></a:b>;
+<b:c.x></b:c.x>;
+<this:b></this:b>;
diff --git a/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.symbols b/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.symbols
new file mode 100644
index 00000000000..405838180ce
--- /dev/null
+++ b/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.symbols
@@ -0,0 +1,31 @@
+=== tests/cases/conformance/jsx/checkJsxNamespaceNamesQuestionableForms.tsx ===
+declare namespace JSX {
+>JSX : Symbol(JSX, Decl(checkJsxNamespaceNamesQuestionableForms.tsx, 0, 0))
+
+    interface IntrinsicElements {
+>IntrinsicElements : Symbol(IntrinsicElements, Decl(checkJsxNamespaceNamesQuestionableForms.tsx, 0, 23))
+
+        'this:b': any;
+>'this:b' : Symbol(IntrinsicElements['this:b'], Decl(checkJsxNamespaceNamesQuestionableForms.tsx, 1, 33))
+
+        'b:c': {
+>'b:c' : Symbol(IntrinsicElements['b:c'], Decl(checkJsxNamespaceNamesQuestionableForms.tsx, 2, 22))
+
+            x: any
+>x : Symbol(x, Decl(checkJsxNamespaceNamesQuestionableForms.tsx, 3, 16))
+
+        };
+        'a:b': any;
+>'a:b' : Symbol(IntrinsicElements['a:b'], Decl(checkJsxNamespaceNamesQuestionableForms.tsx, 5, 10))
+    }
+}
+
+<a:b></a:b>;
+>a:b : Symbol(JSX.IntrinsicElements['a:b'], Decl(checkJsxNamespaceNamesQuestionableForms.tsx, 5, 10))
+>a:b : Symbol(JSX.IntrinsicElements['a:b'], Decl(checkJsxNamespaceNamesQuestionableForms.tsx, 5, 10))
+
+<b:c.x></b:c.x>;
+<this:b></this:b>;
+>this:b : Symbol(JSX.IntrinsicElements['this:b'], Decl(checkJsxNamespaceNamesQuestionableForms.tsx, 1, 33))
+>this:b : Symbol(JSX.IntrinsicElements['this:b'], Decl(checkJsxNamespaceNamesQuestionableForms.tsx, 1, 33))
+
diff --git a/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.types b/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.types
new file mode 100644
index 00000000000..9f999220322
--- /dev/null
+++ b/tests/baselines/reference/checkJsxNamespaceNamesQuestionableForms.types
@@ -0,0 +1,37 @@
+=== tests/cases/conformance/jsx/checkJsxNamespaceNamesQuestionableForms.tsx ===
+declare namespace JSX {
+    interface IntrinsicElements {
+        'this:b': any;
+>'this:b' : any
+
+        'b:c': {
+>'b:c' : { x: any; }
+
+            x: any
+>x : any
+
+        };
+        'a:b': any;
+>'a:b' : any
+    }
+}
+
+<a:b></a:b>;
+><a:b></a:b> : any
+>a:b : any
+>a:b : any
+
+<b:c.x></b:c.x>;
+><b:c.x></b:c.x> : any
+>b:c.x : any
+>b:c : any
+>x : any
+>b:c.x : any
+>b:c : any
+>x : any
+
+<this:b></this:b>;
+><this:b></this:b> : any
+>this:b : any
+>this:b : any
+
diff --git a/tests/baselines/reference/jsxInvalidEsprimaTestSuite.errors.txt b/tests/baselines/reference/jsxInvalidEsprimaTestSuite.errors.txt
index be20bc527a5..ed0df0cdd66 100644
--- a/tests/baselines/reference/jsxInvalidEsprimaTestSuite.errors.txt
+++ b/tests/baselines/reference/jsxInvalidEsprimaTestSuite.errors.txt
@@ -77,6 +77,7 @@ tests/cases/conformance/jsx/6.tsx(1,4): error TS17002: Expected corresponding JS
 tests/cases/conformance/jsx/7.tsx(1,13): error TS1002: Unterminated string literal.
 tests/cases/conformance/jsx/8.tsx(1,6): error TS17002: Expected corresponding JSX closing tag for 'a:b'.
 tests/cases/conformance/jsx/9.tsx(1,2): error TS2304: Cannot find name 'a:b'.
+tests/cases/conformance/jsx/9.tsx(1,2): error TS2633: JSX property access expressions cannot include JSX namespace names
 tests/cases/conformance/jsx/9.tsx(1,10): error TS2304: Cannot find name 'a:b'.
 
 
@@ -128,10 +129,12 @@ tests/cases/conformance/jsx/9.tsx(1,10): error TS2304: Cannot find name 'a:b'.
     <a:b></b>;
          ~~~~
 !!! error TS17002: Expected corresponding JSX closing tag for 'a:b'.
-==== tests/cases/conformance/jsx/9.tsx (2 errors) ====
+==== tests/cases/conformance/jsx/9.tsx (3 errors) ====
     <a:b.c></a:b.c>;
      ~~~
 !!! error TS2304: Cannot find name 'a:b'.
+     ~~~
+!!! error TS2633: JSX property access expressions cannot include JSX namespace names
              ~~~
 !!! error TS2304: Cannot find name 'a:b'.
 ==== tests/cases/conformance/jsx/10.tsx (6 errors) ====
diff --git a/tests/cases/conformance/jsx/checkJsxNamespaceNamesQuestionableForms.tsx b/tests/cases/conformance/jsx/checkJsxNamespaceNamesQuestionableForms.tsx
new file mode 100644
index 00000000000..e1688610a0c
--- /dev/null
+++ b/tests/cases/conformance/jsx/checkJsxNamespaceNamesQuestionableForms.tsx
@@ -0,0 +1,14 @@
+// @jsx: preserve
+declare namespace JSX {
+    interface IntrinsicElements {
+        'this:b': any;
+        'b:c': {
+            x: any
+        };
+        'a:b': any;
+    }
+}
+
+<a:b></a:b>;
+<b:c.x></b:c.x>;
+<this:b></this:b>;
\ No newline at end of file