diff --git a/mrbgems/mruby-struct/src/struct.c b/mrbgems/mruby-struct/src/struct.c
index 4c4a23272..3f7c90799 100644
--- a/mrbgems/mruby-struct/src/struct.c
+++ b/mrbgems/mruby-struct/src/struct.c
@@ -258,12 +258,24 @@ mrb_struct_s_def(mrb_state *mrb, mrb_value klass)
   mrb_value b;
   const mrb_value *argv;
   mrb_int argc;
+  mrb_value keyword_init_val = mrb_nil_value();
 
   mrb_get_args(mrb, "*&", &argv, &argc, &b);
   if (argc == 0) {
     mrb_raise(mrb, E_ARGUMENT_ERROR, "wrong number of arguments (given 0, expected 1+)");
   }
 
+  /* Check for keyword_init option in arguments */
+  if (argc > 0 && mrb_hash_p(argv[argc-1])) {
+    mrb_value options = argv[argc-1];
+    mrb_sym keyword_init_sym = mrb_intern_lit(mrb, "keyword_init");
+
+    if (mrb_hash_key_p(mrb, options, mrb_symbol_value(keyword_init_sym))) {
+      keyword_init_val = mrb_hash_get(mrb, options, mrb_symbol_value(keyword_init_sym));
+      argc--; /* Don't treat the options hash as a member name */
+    }
+  }
+
   const mrb_value *pargv = argv;
   mrb_int argcnt = argc;
   if (argc > 0 && !mrb_symbol_p(argv[0])) {
@@ -290,6 +302,10 @@ mrb_struct_s_def(mrb_state *mrb, mrb_value klass)
   }
 
   mrb_value st = make_struct(mrb, name, members, mrb_class_ptr(klass));
+
+  /* Set keyword_init value on the struct class */
+  mrb_iv_set(mrb, st, mrb_intern_lit(mrb, "@__keyword_init__"), keyword_init_val);
+
   if (!mrb_nil_p(b)) {
     mrb_yield_with_class(mrb, b, 1, &st, st, mrb_class_ptr(st));
   }
@@ -317,14 +333,79 @@ mrb_struct_initialize_withArg(mrb_state *mrb, mrb_int argc, const mrb_value *arg
   return self;
 }
 
+static mrb_value
+mrb_struct_initialize_withKw(mrb_state *mrb, mrb_value hash, mrb_value self)
+{
+  mrb_value members = struct_members(mrb, self);
+  mrb_int member_count = num_members(mrb, self);
+
+  /* Initialize members from hash, defaulting to nil */
+  for (mrb_int i = 0; i < member_count; i++) {
+    mrb_value member = RARRAY_PTR(members)[i];
+    if (mrb_hash_key_p(mrb, hash, member)) {
+      mrb_value val = mrb_hash_get(mrb, hash, member);
+      mrb_ary_set(mrb, self, i, val);
+    }
+    else {
+      mrb_ary_set(mrb, self, i, mrb_nil_value());
+    }
+  }
+
+  /* Create a hash of valid members for faster lookup */
+  mrb_value members_hash = mrb_hash_new(mrb);
+  for (mrb_int i = 0; i < RARRAY_LEN(members); i++) {
+    mrb_hash_set(mrb, members_hash, RARRAY_PTR(members)[i], mrb_true_value());
+  }
+
+  /* Check if all keys in the hash are valid members */
+  mrb_value invalid_keys = mrb_ary_new(mrb);
+  mrb_value keys = mrb_hash_keys(mrb, hash);
+  for (mrb_int i = 0; i < RARRAY_LEN(keys); i++) {
+    mrb_value key = RARRAY_PTR(keys)[i];
+    if (!mrb_hash_key_p(mrb, members_hash, key)) {
+      mrb_ary_push(mrb, invalid_keys, key);
+    }
+  }
+
+  /* If there are any invalid keys, raise an error with all of them */
+  if (RARRAY_LEN(invalid_keys) > 0) {
+    mrb_value keys_str = mrb_funcall(mrb, invalid_keys, "join", 1, mrb_str_new_lit(mrb, ", "));
+    mrb_raisef(mrb, E_ARGUMENT_ERROR, "unknown keywords: %S", keys_str);
+  }
+
+  return self;
+}
+
 static mrb_value
 mrb_struct_initialize(mrb_state *mrb, mrb_value self)
 {
   const mrb_value *argv;
   mrb_int argc;
+  mrb_value klass, keyword_init;
 
   mrb_get_args(mrb, "*", &argv, &argc);
-  return mrb_struct_initialize_withArg(mrb, argc, argv, self);
+
+  klass = mrb_obj_value(mrb_obj_class(mrb, self));
+  keyword_init = mrb_iv_get(mrb, klass, mrb_intern_lit(mrb, "@__keyword_init__"));
+
+  if (mrb_test(keyword_init)) { /* keyword_init: true or other truthy value */
+    if (argc > 1 || (argc == 1 && !mrb_hash_p(argv[0]))) {
+      mrb_raise(mrb, E_ARGUMENT_ERROR, "wrong arguments, expected keyword arguments");
+    }
+    mrb_value hash = (argc == 1) ? argv[0] : mrb_hash_new(mrb);
+    return mrb_struct_initialize_withKw(mrb, hash, self);
+  }
+  else if (mrb_equal(mrb, keyword_init, mrb_false_value())) { /* keyword_init: false */
+    return mrb_struct_initialize_withArg(mrb, argc, argv, self);
+  }
+  else { /* keyword_init: nil (default) */
+    if (argc == 1 && mrb_hash_p(argv[0])) {
+      return mrb_struct_initialize_withKw(mrb, argv[0], self);
+    }
+    else {
+      return mrb_struct_initialize_withArg(mrb, argc, argv, self);
+    }
+  }
 }
 
 /* 15.2.18.4.9  */
diff --git a/mrbgems/mruby-struct/test/struct.rb b/mrbgems/mruby-struct/test/struct.rb
index d10dc866c..deed70680 100644
--- a/mrbgems/mruby-struct/test/struct.rb
+++ b/mrbgems/mruby-struct/test/struct.rb
@@ -229,3 +229,75 @@ assert 'method visibility with Struct' do
     c.new.bad!
   end
 end
+
+assert "Struct initialize with keyword arguments" do
+  c = Struct.new(:foo, :bar)
+
+  o = c.new(foo: 1, bar: 2)
+  assert_equal 1, o.foo
+  assert_equal 2, o.bar
+
+  o2 = c.new(bar: 1, foo: 2)
+  assert_equal 2, o2.foo
+  assert_equal 1, o2.bar
+
+  o3 = c.new(foo: :test)
+  assert_equal :test, o3.foo
+  assert_equal nil, o3.bar
+
+  o4 = c.new
+  assert_equal nil, o4.foo
+  assert_equal nil, o4.bar
+
+  assert_raise_with_message_pattern(ArgumentError, "unknown keywords: roo, baq") do
+    c.new(foo: 1, roo: nil, baq: :test)
+  end
+end
+
+assert "Struct initialize when :keyword_init is true" do
+  c = Struct.new(:foo, :bar, keyword_init: true)
+
+  o = c.new(foo: 1, bar: 2)
+  assert_equal 1, o.foo
+  assert_equal 2, o.bar
+
+  o2 = c.new
+  assert_equal nil, o2.foo
+  assert_equal nil, o2.bar
+
+  assert_raise(ArgumentError) do
+    c.new(1, 2)
+  end
+
+  assert_raise(ArgumentError) do
+    c.new({foo: 1}, {bar: 2})
+  end
+end
+
+assert "Struct initialize when :keyword_init is false" do
+  c = Struct.new(:foo, :bar, keyword_init: false)
+
+  o = c.new(1, 2)
+  assert_equal 1, o.foo
+  assert_equal 2, o.bar
+
+  o2 = c.new(foo: 1, bar: 2)
+  assert_equal({foo: 1, bar: 2}, o2.foo)
+  assert_equal nil, o2.bar
+
+  o3 = c.new
+  assert_equal nil, o3.foo
+  assert_equal nil, o3.bar
+end
+
+assert "Struct initialize when :keyword_init is non-boolean value (treat as true)" do
+  c = Struct.new(:foo, :bar, keyword_init: 12)
+
+  o = c.new(foo: 1, bar: 2)
+  assert_equal 1, o.foo
+  assert_equal 2, o.bar
+
+  assert_raise(ArgumentError) do
+    c.new(1, 2)
+  end
+end