diff --git a/src/LuaTransformer.ts b/src/LuaTransformer.ts
index 0df3f10ed..86f680583 100644
--- a/src/LuaTransformer.ts
+++ b/src/LuaTransformer.ts
@@ -2396,6 +2396,10 @@ export class LuaTransformer {
                 return this.transformBinaryBitOperation(tsOriginal, left, right, operator);
             default:
                 const luaOperator = this.transformBinaryOperator(operator, tsOriginal);
+                if (luaOperator === tstl.SyntaxKind.ConcatOperator) {
+                    left = this.wrapInToStringForConcat(left);
+                    right = this.wrapInToStringForConcat(right);
+                }
                 return tstl.createBinaryExpression(left, right, luaOperator, tsOriginal);
         }
     }
@@ -4091,8 +4095,7 @@ export class LuaTransformer {
         }
 
         expression.templateSpans.forEach(span => {
-            const expr = this.transformExpression(span.expression);
-            parts.push(tstl.createCallExpression(tstl.createIdentifier("tostring"), [expr]));
+            parts.push(this.wrapInToStringForConcat(this.transformExpression(span.expression)));
 
             const text = tsHelper.escapeString(span.literal.text);
             if (text.length > 0) {
@@ -4487,7 +4490,13 @@ export class LuaTransformer {
 
     private wrapInFunctionCall(expression: tstl.Expression): tstl.FunctionExpression {
         const returnStatement = tstl.createReturnStatement([expression]);
-        return tstl.createFunctionExpression(tstl.createBlock([returnStatement]));
+        return tstl.createFunctionExpression(
+            tstl.createBlock([returnStatement]),
+            undefined,
+            undefined,
+            undefined,
+            tstl.FunctionExpressionFlags.Inline
+        );
     }
 
     private wrapInTable(...expressions: tstl.Expression[]): tstl.ParenthesizedExpression {
@@ -4495,6 +4504,16 @@ export class LuaTransformer {
         return tstl.createParenthesizedExpression(tstl.createTableExpression(fields));
     }
 
+    private wrapInToStringForConcat(expression: tstl.Expression): tstl.Expression {
+        if (tstl.isStringLiteral(expression)
+            || tstl.isNumericLiteral(expression)
+            || (tstl.isBinaryExpression(expression) && expression.operator === tstl.SyntaxKind.ConcatOperator))
+        {
+            return expression;
+        }
+        return tstl.createCallExpression(tstl.createIdentifier("tostring"), [expression]);
+    }
+
     private expressionPlusOne(expression: tstl.Expression): tstl.BinaryExpression {
         if (tstl.isBinaryExpression(expression)) {
             expression = tstl.createParenthesizedExpression(expression);
diff --git a/test/translation/__snapshots__/transformation.spec.ts.snap b/test/translation/__snapshots__/transformation.spec.ts.snap
index b0baaa3dd..2a8c00c78 100644
--- a/test/translation/__snapshots__/transformation.spec.ts.snap
+++ b/test/translation/__snapshots__/transformation.spec.ts.snap
@@ -14,7 +14,7 @@ local backQuoteInTemplateString = \\"\` \` \`\\";
 local escapedCharsInQuotes = \\"\\\\\\\\ \\\\0 \\\\b \\\\t \\\\n \\\\v \\\\f \\\\\\" \\\\' \`\\";
 local escapedCharsInDoubleQUotes = \\"\\\\\\\\ \\\\0 \\\\b \\\\t \\\\n \\\\v \\\\f \\\\\\" \\\\'\\";
 local escapedCharsInTemplateString = \\"\\\\\\\\ \\\\0 \\\\b \\\\t \\\\n \\\\v \\\\f \\\\\\" \\\\' \`\\";
-local nonEmptyTemplateString = \\"Level 0: \\\\n\\\\t \\" .. tostring(\\"Level 1: \\\\n\\\\t\\\\t \\" .. tostring(\\"Level 3: \\\\n\\\\t\\\\t\\\\t \\" .. tostring(\\"Last level \\\\n --\\") .. \\" \\\\n --\\") .. \\" \\\\n --\\") .. \\" \\\\n --\\";"
+local nonEmptyTemplateString = \\"Level 0: \\\\n\\\\t \\" .. \\"Level 1: \\\\n\\\\t\\\\t \\" .. \\"Level 3: \\\\n\\\\t\\\\t\\\\t \\" .. \\"Last level \\\\n --\\" .. \\" \\\\n --\\" .. \\" \\\\n --\\" .. \\" \\\\n --\\";"
 `;
 
 exports[`Transformation (classExtension1) 1`] = `
diff --git a/test/unit/string.spec.ts b/test/unit/string.spec.ts
index 2b7cd4362..dfb494c62 100644
--- a/test/unit/string.spec.ts
+++ b/test/unit/string.spec.ts
@@ -34,14 +34,41 @@ test.each([
     { a: "test", b: "hello", c: "bye" },
     { a: "test", b: 42, c: "bye" },
     { a: "test", b: 42, c: 12 },
+    { a: "test", b: 42, c: true },
+    { a: false, b: 42, c: 12 },
 ])("Template Strings (%p)", ({ a, b, c }) => {
-    const a1 = typeof a === "string" ? "'" + a + "'" : a;
-    const b1 = typeof b === "string" ? "'" + b + "'" : b;
-    const c1 = typeof c === "string" ? "'" + c + "'" : c;
+    const a1 = typeof a === "string" ? `'${a}'` : a;
+    const b1 = typeof b === "string" ? `'${b}'` : b;
+    const c1 = typeof c === "string" ? `'${c}'` : c;
 
-    const result = util.transpileAndExecute(
-        "let a = " + a1 + "; let b = " + b1 + "; let c = " + c1 + "; return `${a} ${b} test ${c}`;",
-    );
+    const result = util.transpileAndExecute(`
+        let a = ${a1};
+        let b = ${b1};
+        let c = ${c1};
+        return \`${a} ${b} test ${c}\`;
+        `);
+
+    expect(result).toBe(`${a} ${b} test ${c}`);
+});
+
+test.each([
+    { a: 12, b: 23, c: 43 },
+    { a: "test", b: "hello", c: "bye" },
+    { a: "test", b: 42, c: "bye" },
+    { a: "test", b: 42, c: 12 },
+    { a: "test", b: 42, c: true },
+    { a: false, b: 42, c: 12 },
+])("String Concat Operator (%p)", ({ a, b, c }) => {
+    const a1 = typeof a === "string" ? `'${a}'` : a;
+    const b1 = typeof b === "string" ? `'${b}'` : b;
+    const c1 = typeof c === "string" ? `'${c}'` : c;
+
+    const result = util.transpileAndExecute(`
+        let a = ${a1};
+        let b = ${b1};
+        let c = ${c1};
+        return a + " " + b + " test " + c;
+        `);
 
     expect(result).toBe(`${a} ${b} test ${c}`);
 });