diff --git a/lib/rules/no-param-reassign.js b/lib/rules/no-param-reassign.js
index 243bb6412cf..349345c148a 100644
--- a/lib/rules/no-param-reassign.js
+++ b/lib/rules/no-param-reassign.js
@@ -107,6 +107,14 @@ module.exports = {
 
                         break;
 
+                    // EXCLUDES: e.g. (foo ? a : b).c = bar;
+                    case "ConditionalExpression":
+                        if (parent.test === node) {
+                            return false;
+                        }
+
+                        break;
+
                     // no default
                 }
 
diff --git a/tests/lib/rules/no-param-reassign.js b/tests/lib/rules/no-param-reassign.js
index 5d009c338f3..40156f481ec 100644
--- a/tests/lib/rules/no-param-reassign.js
+++ b/tests/lib/rules/no-param-reassign.js
@@ -32,6 +32,8 @@ ruleTester.run("no-param-reassign", rule, {
         { code: "function foo(a) { bar(a.b).c = 0; }", options: [{ props: true }] },
         { code: "function foo(a) { data[a.b] = 0; }", options: [{ props: true }] },
         { code: "function foo(a) { +a.b; }", options: [{ props: true }] },
+        { code: "function foo(a) { (a ? [] : [])[0] = 1; }", options: [{ props: true }] },
+        { code: "function foo(a) { (a.b ? [] : [])[0] = 1; }", options: [{ props: true }] },
         { code: "function foo(a) { a.b = 0; }", options: [{ props: true, ignorePropertyModificationsFor: ["a"] }] },
         { code: "function foo(a) { ++a.b; }", options: [{ props: true, ignorePropertyModificationsFor: ["a"] }] },
         { code: "function foo(a) { delete a.b; }", options: [{ props: true, ignorePropertyModificationsFor: ["a"] }] },
@@ -87,6 +89,11 @@ ruleTester.run("no-param-reassign", rule, {
             options: [{ props: true }],
             errors: [{ message: "Assignment to property of function parameter 'bar'." }]
         },
+        {
+            code: "function foo(bar) { (bar ? bar : [])[0] = 1; }",
+            options: [{ props: true }],
+            errors: [{ message: "Assignment to property of function parameter 'bar'." }]
+        },
         {
             code: "function foo(bar) { [bar.a] = []; }",
             options: [{ props: true }],