diff --git a/packages/babel-plugin-proposal-optional-chaining/src/index.js b/packages/babel-plugin-proposal-optional-chaining/src/index.js
index 3fb69e104bf5..f9f8f99ab84d 100644
--- a/packages/babel-plugin-proposal-optional-chaining/src/index.js
+++ b/packages/babel-plugin-proposal-optional-chaining/src/index.js
@@ -35,9 +35,10 @@ export default declare((api, options) => {
       optionalPath.isOptionalCallExpression()
     ) {
       const { node } = optionalPath;
-      const childPath = skipTransparentExprWrappers(
-        optionalPath.get("object") ?? optionalPath.get("callee"),
-      );
+      const childKey = optionalPath.isOptionalMemberExpression()
+        ? "object"
+        : "callee";
+      const childPath = skipTransparentExprWrappers(optionalPath.get(childKey));
       if (node.optional) {
         return !scope.isStatic(childPath.node);
       }
diff --git a/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params-loose/input.js b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params-loose/input.js
new file mode 100644
index 000000000000..882511b447f8
--- /dev/null
+++ b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params-loose/input.js
@@ -0,0 +1,9 @@
+function f(a = x?.y) {}
+
+function g({ a, b = a?.c }) {}
+
+function h(a, { b = a.b?.c?.d.e }) {}
+
+function i(a, { b = (a.b?.c?.d).e }) {}
+
+function j(a, { b = a?.b?.c().d.e }) {}
diff --git a/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params-loose/options.json b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params-loose/options.json
new file mode 100644
index 000000000000..39ea3f99c7ff
--- /dev/null
+++ b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params-loose/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["proposal-optional-chaining", { "loose": true }]]
+}
diff --git a/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params-loose/output.js b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params-loose/output.js
new file mode 100644
index 000000000000..f5cda260cbfe
--- /dev/null
+++ b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params-loose/output.js
@@ -0,0 +1,34 @@
+function f(a = (() => {
+  var _x;
+
+  return (_x = x) == null ? void 0 : _x.y;
+})()) {}
+
+function g({
+  a,
+  b = a == null ? void 0 : a.c
+}) {}
+
+function h(a, {
+  b = (() => {
+    var _a$b, _a$b$c;
+
+    return (_a$b = a.b) == null ? void 0 : (_a$b$c = _a$b.c) == null ? void 0 : _a$b$c.d.e;
+  })()
+}) {}
+
+function i(a, {
+  b = (() => {
+    var _a$b2, _a$b2$c;
+
+    return (_a$b2 = a.b) == null ? void 0 : (_a$b2$c = _a$b2.c) == null ? void 0 : _a$b2$c.d;
+  })().e
+}) {}
+
+function j(a, {
+  b = (() => {
+    var _a$b3;
+
+    return a == null ? void 0 : (_a$b3 = a.b) == null ? void 0 : _a$b3.c().d.e;
+  })()
+}) {}
diff --git a/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params/input.js b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params/input.js
index 802d92c1342c..882511b447f8 100644
--- a/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params/input.js
+++ b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params/input.js
@@ -5,3 +5,5 @@ function g({ a, b = a?.c }) {}
 function h(a, { b = a.b?.c?.d.e }) {}
 
 function i(a, { b = (a.b?.c?.d).e }) {}
+
+function j(a, { b = a?.b?.c().d.e }) {}
diff --git a/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params/output.js b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params/output.js
index e2c8101d8d32..8d7909dc76fa 100644
--- a/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params/output.js
+++ b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/general/in-function-params/output.js
@@ -24,3 +24,11 @@ function i(a, {
     return (_a$b2 = a.b) === null || _a$b2 === void 0 ? void 0 : (_a$b2$c = _a$b2.c) === null || _a$b2$c === void 0 ? void 0 : _a$b2$c.d;
   })().e
 }) {}
+
+function j(a, {
+  b = (() => {
+    var _a$b3;
+
+    return a === null || a === void 0 ? void 0 : (_a$b3 = a.b) === null || _a$b3 === void 0 ? void 0 : _a$b3.c().d.e;
+  })()
+}) {}