diff --git a/Userland/Libraries/LibJS/Runtime/Value.cpp b/Userland/Libraries/LibJS/Runtime/Value.cpp
index 77fc975649..7c3f9445d5 100644
--- a/Userland/Libraries/LibJS/Runtime/Value.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Value.cpp
@@ -500,6 +500,11 @@ ThrowCompletionOr<Value> Value::to_number(GlobalObject& global_object) const
         auto parsed_double = strtod(string.characters(), &endptr);
         if (*endptr)
             return js_nan();
+        // NOTE: Per the spec only exactly [+-]Infinity should result in infinity
+        //       but strtod gives infinity for any case-insensitive 'infinity' or 'inf' string.
+        if (isinf(parsed_double) && string.contains('i', AK::CaseSensitivity::CaseInsensitive))
+            return js_nan();
+
         return Value(parsed_double);
     }
     case SYMBOL_TAG:
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Number/Number.js b/Userland/Libraries/LibJS/Tests/builtins/Number/Number.js
index 7ee0f557a9..7a237dd21b 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/Number/Number.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/Number/Number.js
@@ -17,11 +17,18 @@ test("constructor without new", () => {
     expect(Number("Infinity")).toBe(Infinity);
     expect(Number("+Infinity")).toBe(Infinity);
     expect(Number("-Infinity")).toBe(-Infinity);
+    expect(Number("infinity")).toBeNaN();
+    expect(Number("-infinity")).toBeNaN();
+    expect(Number("INFINITY")).toBeNaN();
+    expect(Number("-INFINITY")).toBeNaN();
+    expect(Number("inf")).toBeNaN();
     expect(Number(undefined)).toBeNaN();
     expect(Number({})).toBeNaN();
     expect(Number({ a: 1 })).toBeNaN();
     expect(Number([1, 2, 3])).toBeNaN();
     expect(Number("foo")).toBeNaN();
+    expect(Number("10e10000")).toBe(Infinity);
+    expect(Number("-10e10000")).toBe(-Infinity);
 });
 
 test("constructor with new", () => {
@@ -38,9 +45,16 @@ test("constructor with new", () => {
     expect(new Number("Infinity").valueOf()).toBe(Infinity);
     expect(new Number("+Infinity").valueOf()).toBe(Infinity);
     expect(new Number("-Infinity").valueOf()).toBe(-Infinity);
+    expect(new Number("infinity").valueOf()).toBeNaN();
+    expect(new Number("-infinity").valueOf()).toBeNaN();
+    expect(new Number("INFINITY").valueOf()).toBeNaN();
+    expect(new Number("-INFINITY").valueOf()).toBeNaN();
+    expect(new Number("inf").valueOf()).toBeNaN();
     expect(new Number(undefined).valueOf()).toBeNaN();
     expect(new Number({}).valueOf()).toBeNaN();
     expect(new Number({ a: 1 }).valueOf()).toBeNaN();
     expect(new Number([1, 2, 3]).valueOf()).toBeNaN();
     expect(new Number("foo").valueOf()).toBeNaN();
+    expect(new Number("10e10000").valueOf()).toBe(Infinity);
+    expect(new Number("-10e10000").valueOf()).toBe(-Infinity);
 });