diff --git a/hash.c b/hash.c
index 69a768d4ce..8c20791ede 100644
--- a/hash.c
+++ b/hash.c
@@ -6639,31 +6639,26 @@ env_update(int argc, VALUE *argv, VALUE env)
     return env;
 }
 
+NORETURN(static VALUE env_clone(int, VALUE *, VALUE));
 /*
  * call-seq:
- *   ENV.clone(freeze: nil) -> ENV
+ *   ENV.clone(freeze: nil) # raises TypeError
  *
- * Returns ENV itself, and warns because ENV is a wrapper for the
- * process-wide environment variables and a clone is useless.
- * If +freeze+ keyword is given and not +nil+ or +false+, raises ArgumentError.
- * If +freeze+ keyword is given and +true+, raises TypeError, as ENV storage
- * cannot be frozen.
+ * Raises TypeError, because ENV is a wrapper for the process-wide
+ * environment variables and a clone is useless.
+ * Use #to_h to get a copy of ENV data as a hash.
  */
 static VALUE
 env_clone(int argc, VALUE *argv, VALUE obj)
 {
     if (argc) {
-        VALUE opt, kwfreeze;
+        VALUE opt;
         if (rb_scan_args(argc, argv, "0:", &opt) < argc) {
-            kwfreeze = rb_get_freeze_opt(1, &opt);
-            if (RTEST(kwfreeze)) {
-                rb_raise(rb_eTypeError, "cannot freeze ENV");
-            }
+            rb_get_freeze_opt(1, &opt);
         }
     }
 
-    rb_warn_deprecated("ENV.clone", "ENV.to_h");
-    return envtbl;
+    rb_raise(rb_eTypeError, "Cannot clone ENV, use ENV.to_h to get a copy of ENV as a hash");
 }
 
 NORETURN(static VALUE env_dup(VALUE));
diff --git a/test/ruby/test_env.rb b/test/ruby/test_env.rb
index e9eaf144a1..cdadeac148 100644
--- a/test/ruby/test_env.rb
+++ b/test/ruby/test_env.rb
@@ -69,25 +69,20 @@ class TestEnv < Test::Unit::TestCase
   end
 
   def test_clone
-    warning = /ENV\.clone is deprecated; use ENV\.to_h instead/
-    clone = assert_deprecated_warning(warning) {
+    message = /Cannot clone ENV/
+    assert_raise_with_message(TypeError, message) {
       ENV.clone
     }
-    assert_same(ENV, clone)
-
-    clone = assert_deprecated_warning(warning) {
+    assert_raise_with_message(TypeError, message) {
       ENV.clone(freeze: false)
     }
-    assert_same(ENV, clone)
-
-    clone = assert_deprecated_warning(warning) {
+    assert_raise_with_message(TypeError, message) {
       ENV.clone(freeze: nil)
     }
-    assert_same(ENV, clone)
-
-    assert_raise(TypeError) {
+    assert_raise_with_message(TypeError, message) {
       ENV.clone(freeze: true)
     }
+
     assert_raise(ArgumentError) {
       ENV.clone(freeze: 1)
     }
@@ -688,37 +683,6 @@ class TestEnv < Test::Unit::TestCase
     end;
   end
 
-  def test_clone_in_ractor
-    assert_ractor(<<-"end;")
-      r = Ractor.new do
-        original_warning_state = Warning[:deprecated]
-        Warning[:deprecated] = false
-
-        begin
-          Ractor.yield ENV.clone.object_id
-          Ractor.yield ENV.clone(freeze: false).object_id
-          Ractor.yield ENV.clone(freeze: nil).object_id
-
-          #{str_for_yielding_exception_class("ENV.clone(freeze: true)")}
-          #{str_for_yielding_exception_class("ENV.clone(freeze: 1)")}
-          #{str_for_yielding_exception_class("ENV.clone(foo: false)")}
-          #{str_for_yielding_exception_class("ENV.clone(1)")}
-          #{str_for_yielding_exception_class("ENV.clone(1, foo: false)")}
-
-        ensure
-          Warning[:deprecated] = original_warning_state
-        end
-      end
-      assert_equal(ENV.object_id, r.take)
-      assert_equal(ENV.object_id, r.take)
-      assert_equal(ENV.object_id, r.take)
-      #{str_for_assert_raise_on_yielded_exception_class(TypeError, "r")}
-      4.times do
-        #{str_for_assert_raise_on_yielded_exception_class(ArgumentError, "r")}
-      end
-    end;
-  end
-
   def test_has_value_in_ractor
     assert_ractor(<<-"end;")
       r = Ractor.new do