diff --git a/src/LuaTransformer.ts b/src/LuaTransformer.ts
index 4138f2af2..ac8f49578 100644
--- a/src/LuaTransformer.ts
+++ b/src/LuaTransformer.ts
@@ -4350,17 +4350,14 @@ export class LuaTransformer {
             case "concat":
                 return this.transformLuaLibFunction(LuaLibFeature.StringConcat, node, caller, ...params);
             case "indexOf":
-                const stringExpression =
-                    node.arguments.length === 1
-                        ? this.createStringCall("find", node, caller, params[0])
-                        : this.createStringCall(
-                              "find",
-                              node,
-                              caller,
-                              params[0],
-                              this.expressionPlusOne(params[1]),
-                              tstl.createBooleanLiteral(true)
-                          );
+                const stringExpression = this.createStringCall(
+                    "find",
+                    node,
+                    caller,
+                    params[0],
+                    params[1] ? this.expressionPlusOne(params[1]) : tstl.createNilLiteral(),
+                    tstl.createBooleanLiteral(true)
+                );
 
                 return tstl.createParenthesizedExpression(
                     tstl.createBinaryExpression(
diff --git a/test/unit/string.spec.ts b/test/unit/string.spec.ts
index 8768818cf..9590c478d 100644
--- a/test/unit/string.spec.ts
+++ b/test/unit/string.spec.ts
@@ -132,6 +132,7 @@ test.each([
     { inp: "hello test", searchValue: "t" },
     { inp: "hello test", searchValue: "h" },
     { inp: "hello test", searchValue: "invalid" },
+    { inp: "hello.test", searchValue: "." },
 ])("string.indexOf (%p)", ({ inp, searchValue }) => {
     const result = util.transpileAndExecute(`return "${inp}".indexOf("${searchValue}")`);