diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 5d8b10eb3da..c0b96f2d986 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -19684,7 +19684,9 @@ namespace ts {
             // A place where we actually *are* concerned with the expressions' types are
             // in tagged templates.
             forEach(node.templateSpans, templateSpan => {
-                checkExpression(templateSpan.expression);
+                if (maybeTypeOfKind(checkExpression(templateSpan.expression), TypeFlags.ESSymbolLike)) {
+                    error(templateSpan.expression, Diagnostics.Type_0_cannot_be_converted_to_type_1, typeToString(esSymbolType), typeToString(stringType));
+                }
             });
 
             return stringType;
diff --git a/tests/baselines/reference/noImplicitSymbolToString.errors.txt b/tests/baselines/reference/noImplicitSymbolToString.errors.txt
new file mode 100644
index 00000000000..6dae5c5d76f
--- /dev/null
+++ b/tests/baselines/reference/noImplicitSymbolToString.errors.txt
@@ -0,0 +1,32 @@
+tests/cases/compiler/noImplicitSymbolToString.ts(6,30): error TS2352: Type 'symbol' cannot be converted to type 'string'.
+tests/cases/compiler/noImplicitSymbolToString.ts(7,30): error TS2469: The '+' operator cannot be applied to type 'symbol'.
+tests/cases/compiler/noImplicitSymbolToString.ts(8,8): error TS2469: The '+=' operator cannot be applied to type 'symbol'.
+tests/cases/compiler/noImplicitSymbolToString.ts(13,47): error TS2352: Type 'symbol' cannot be converted to type 'string'.
+tests/cases/compiler/noImplicitSymbolToString.ts(13,90): error TS2352: Type 'symbol' cannot be converted to type 'string'.
+
+
+==== tests/cases/compiler/noImplicitSymbolToString.ts (5 errors) ====
+    // Fix #19666
+    
+    let symbol!: symbol;
+    let str = "hello ";
+    
+    const templateStr = `hello ${symbol}`;
+                                 ~~~~~~
+!!! error TS2352: Type 'symbol' cannot be converted to type 'string'.
+    const appendStr = "hello " + symbol;
+                                 ~~~~~~
+!!! error TS2469: The '+' operator cannot be applied to type 'symbol'.
+    str += symbol;
+           ~~~~~~
+!!! error TS2469: The '+=' operator cannot be applied to type 'symbol'.
+    
+    let symbolUnionNumber!: symbol | number;
+    let symbolUnionString!: symbol | string;
+    
+    const templateStrUnion = `union with number ${symbolUnionNumber} and union with string ${symbolUnionString}`;
+                                                  ~~~~~~~~~~~~~~~~~
+!!! error TS2352: Type 'symbol' cannot be converted to type 'string'.
+                                                                                             ~~~~~~~~~~~~~~~~~
+!!! error TS2352: Type 'symbol' cannot be converted to type 'string'.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/noImplicitSymbolToString.js b/tests/baselines/reference/noImplicitSymbolToString.js
new file mode 100644
index 00000000000..836d5abe8a9
--- /dev/null
+++ b/tests/baselines/reference/noImplicitSymbolToString.js
@@ -0,0 +1,26 @@
+//// [noImplicitSymbolToString.ts]
+// Fix #19666
+
+let symbol!: symbol;
+let str = "hello ";
+
+const templateStr = `hello ${symbol}`;
+const appendStr = "hello " + symbol;
+str += symbol;
+
+let symbolUnionNumber!: symbol | number;
+let symbolUnionString!: symbol | string;
+
+const templateStrUnion = `union with number ${symbolUnionNumber} and union with string ${symbolUnionString}`;
+
+
+//// [noImplicitSymbolToString.js]
+// Fix #19666
+var symbol;
+var str = "hello ";
+var templateStr = "hello " + symbol;
+var appendStr = "hello " + symbol;
+str += symbol;
+var symbolUnionNumber;
+var symbolUnionString;
+var templateStrUnion = "union with number " + symbolUnionNumber + " and union with string " + symbolUnionString;
diff --git a/tests/baselines/reference/noImplicitSymbolToString.symbols b/tests/baselines/reference/noImplicitSymbolToString.symbols
new file mode 100644
index 00000000000..b2a08e151ab
--- /dev/null
+++ b/tests/baselines/reference/noImplicitSymbolToString.symbols
@@ -0,0 +1,32 @@
+=== tests/cases/compiler/noImplicitSymbolToString.ts ===
+// Fix #19666
+
+let symbol!: symbol;
+>symbol : Symbol(symbol, Decl(noImplicitSymbolToString.ts, 2, 3))
+
+let str = "hello ";
+>str : Symbol(str, Decl(noImplicitSymbolToString.ts, 3, 3))
+
+const templateStr = `hello ${symbol}`;
+>templateStr : Symbol(templateStr, Decl(noImplicitSymbolToString.ts, 5, 5))
+>symbol : Symbol(symbol, Decl(noImplicitSymbolToString.ts, 2, 3))
+
+const appendStr = "hello " + symbol;
+>appendStr : Symbol(appendStr, Decl(noImplicitSymbolToString.ts, 6, 5))
+>symbol : Symbol(symbol, Decl(noImplicitSymbolToString.ts, 2, 3))
+
+str += symbol;
+>str : Symbol(str, Decl(noImplicitSymbolToString.ts, 3, 3))
+>symbol : Symbol(symbol, Decl(noImplicitSymbolToString.ts, 2, 3))
+
+let symbolUnionNumber!: symbol | number;
+>symbolUnionNumber : Symbol(symbolUnionNumber, Decl(noImplicitSymbolToString.ts, 9, 3))
+
+let symbolUnionString!: symbol | string;
+>symbolUnionString : Symbol(symbolUnionString, Decl(noImplicitSymbolToString.ts, 10, 3))
+
+const templateStrUnion = `union with number ${symbolUnionNumber} and union with string ${symbolUnionString}`;
+>templateStrUnion : Symbol(templateStrUnion, Decl(noImplicitSymbolToString.ts, 12, 5))
+>symbolUnionNumber : Symbol(symbolUnionNumber, Decl(noImplicitSymbolToString.ts, 9, 3))
+>symbolUnionString : Symbol(symbolUnionString, Decl(noImplicitSymbolToString.ts, 10, 3))
+
diff --git a/tests/baselines/reference/noImplicitSymbolToString.types b/tests/baselines/reference/noImplicitSymbolToString.types
new file mode 100644
index 00000000000..c21c0e07bfd
--- /dev/null
+++ b/tests/baselines/reference/noImplicitSymbolToString.types
@@ -0,0 +1,38 @@
+=== tests/cases/compiler/noImplicitSymbolToString.ts ===
+// Fix #19666
+
+let symbol!: symbol;
+>symbol : symbol
+
+let str = "hello ";
+>str : string
+>"hello " : "hello "
+
+const templateStr = `hello ${symbol}`;
+>templateStr : string
+>`hello ${symbol}` : string
+>symbol : symbol
+
+const appendStr = "hello " + symbol;
+>appendStr : string
+>"hello " + symbol : string
+>"hello " : "hello "
+>symbol : symbol
+
+str += symbol;
+>str += symbol : string
+>str : string
+>symbol : symbol
+
+let symbolUnionNumber!: symbol | number;
+>symbolUnionNumber : number | symbol
+
+let symbolUnionString!: symbol | string;
+>symbolUnionString : string | symbol
+
+const templateStrUnion = `union with number ${symbolUnionNumber} and union with string ${symbolUnionString}`;
+>templateStrUnion : string
+>`union with number ${symbolUnionNumber} and union with string ${symbolUnionString}` : string
+>symbolUnionNumber : number | symbol
+>symbolUnionString : string | symbol
+
diff --git a/tests/baselines/reference/taggedTemplateStringWithSymbolExpression01.js b/tests/baselines/reference/taggedTemplateStringWithSymbolExpression01.js
new file mode 100644
index 00000000000..4f02e7644f7
--- /dev/null
+++ b/tests/baselines/reference/taggedTemplateStringWithSymbolExpression01.js
@@ -0,0 +1,17 @@
+//// [taggedTemplateStringWithSymbolExpression01.ts]
+// taggedTemplateStringWithSymbolExpression01.ts
+
+declare function foo(template: any, val: symbol): number;
+let x!: symbol;
+
+let result: number = foo`${x}`;
+
+
+//// [taggedTemplateStringWithSymbolExpression01.js]
+// taggedTemplateStringWithSymbolExpression01.ts
+var __makeTemplateObject = (this && this.__makeTemplateObject) || function (cooked, raw) {
+    if (Object.defineProperty) { Object.defineProperty(cooked, "raw", { value: raw }); } else { cooked.raw = raw; }
+    return cooked;
+};
+var x;
+var result = foo(__makeTemplateObject(["", ""], ["", ""]), x);
diff --git a/tests/baselines/reference/taggedTemplateStringWithSymbolExpression01.symbols b/tests/baselines/reference/taggedTemplateStringWithSymbolExpression01.symbols
new file mode 100644
index 00000000000..743d31193d4
--- /dev/null
+++ b/tests/baselines/reference/taggedTemplateStringWithSymbolExpression01.symbols
@@ -0,0 +1,16 @@
+=== tests/cases/compiler/taggedTemplateStringWithSymbolExpression01.ts ===
+// taggedTemplateStringWithSymbolExpression01.ts
+
+declare function foo(template: any, val: symbol): number;
+>foo : Symbol(foo, Decl(taggedTemplateStringWithSymbolExpression01.ts, 0, 0))
+>template : Symbol(template, Decl(taggedTemplateStringWithSymbolExpression01.ts, 2, 21))
+>val : Symbol(val, Decl(taggedTemplateStringWithSymbolExpression01.ts, 2, 35))
+
+let x!: symbol;
+>x : Symbol(x, Decl(taggedTemplateStringWithSymbolExpression01.ts, 3, 3))
+
+let result: number = foo`${x}`;
+>result : Symbol(result, Decl(taggedTemplateStringWithSymbolExpression01.ts, 5, 3))
+>foo : Symbol(foo, Decl(taggedTemplateStringWithSymbolExpression01.ts, 0, 0))
+>x : Symbol(x, Decl(taggedTemplateStringWithSymbolExpression01.ts, 3, 3))
+
diff --git a/tests/baselines/reference/taggedTemplateStringWithSymbolExpression01.types b/tests/baselines/reference/taggedTemplateStringWithSymbolExpression01.types
new file mode 100644
index 00000000000..f1a16a7f8ef
--- /dev/null
+++ b/tests/baselines/reference/taggedTemplateStringWithSymbolExpression01.types
@@ -0,0 +1,18 @@
+=== tests/cases/compiler/taggedTemplateStringWithSymbolExpression01.ts ===
+// taggedTemplateStringWithSymbolExpression01.ts
+
+declare function foo(template: any, val: symbol): number;
+>foo : (template: any, val: symbol) => number
+>template : any
+>val : symbol
+
+let x!: symbol;
+>x : symbol
+
+let result: number = foo`${x}`;
+>result : number
+>foo`${x}` : number
+>foo : (template: any, val: symbol) => number
+>`${x}` : string
+>x : symbol
+
diff --git a/tests/cases/compiler/noImplicitSymbolToString.ts b/tests/cases/compiler/noImplicitSymbolToString.ts
new file mode 100644
index 00000000000..16690d6d845
--- /dev/null
+++ b/tests/cases/compiler/noImplicitSymbolToString.ts
@@ -0,0 +1,13 @@
+// Fix #19666
+
+let symbol!: symbol;
+let str = "hello ";
+
+const templateStr = `hello ${symbol}`;
+const appendStr = "hello " + symbol;
+str += symbol;
+
+let symbolUnionNumber!: symbol | number;
+let symbolUnionString!: symbol | string;
+
+const templateStrUnion = `union with number ${symbolUnionNumber} and union with string ${symbolUnionString}`;
diff --git a/tests/cases/compiler/taggedTemplateStringWithSymbolExpression01.ts b/tests/cases/compiler/taggedTemplateStringWithSymbolExpression01.ts
new file mode 100644
index 00000000000..0cbf3c00e38
--- /dev/null
+++ b/tests/cases/compiler/taggedTemplateStringWithSymbolExpression01.ts
@@ -0,0 +1,6 @@
+// taggedTemplateStringWithSymbolExpression01.ts
+
+declare function foo(template: any, val: symbol): number;
+let x!: symbol;
+
+let result: number = foo`${x}`;