diff --git a/spec/compiler/formatter/formatter_spec.cr b/spec/compiler/formatter/formatter_spec.cr
index f0ee8410bd57..4eb8b39bdd9d 100644
--- a/spec/compiler/formatter/formatter_spec.cr
+++ b/spec/compiler/formatter/formatter_spec.cr
@@ -259,6 +259,177 @@ describe Crystal::Formatter do
   assert_format "def foo\n  1 #\nrescue\nend"
   assert_format "def foo\n  1\n  #\n\n\nrescue\nend", "def foo\n  1\n  #\nrescue\nend"
 
+  assert_format "def foo(@[MyAnn] v); end"
+  assert_format "def foo(@[MyAnn] &); end"
+  assert_format "def foo(@[MyAnn] &block); end"
+  assert_format "def foo(@[MyAnn] & : String -> Nil); end"
+  assert_format "def foo(  @[MyAnn]  v  ); end", "def foo(@[MyAnn] v); end"
+  assert_format "def foo(@[AnnOne] @[AnnTwo] v); end"
+  assert_format "def foo(@[AnnOne]   @[AnnTwo] v); end", "def foo(@[AnnOne] @[AnnTwo] v); end"
+  assert_format "def foo(@[AnnOne]   @[AnnTwo]   &  ); end", "def foo(@[AnnOne] @[AnnTwo] &); end"
+  assert_format "def foo(@[AnnOne]   @[AnnTwo]   &block : Int32 ->  ); end", "def foo(@[AnnOne] @[AnnTwo] &block : Int32 ->); end"
+  assert_format <<-CRYSTAL
+  def foo(
+    @[MyAnn] bar
+  ); end
+  CRYSTAL
+
+  assert_format <<-CRYSTAL
+  def foo(
+    foo,
+    @[MyAnn] &block
+  ); end
+  CRYSTAL
+
+  assert_format <<-CRYSTAL
+  def foo(
+    foo,
+    @[MyAnn]
+    &block
+  ); end
+  CRYSTAL
+
+  assert_format <<-CRYSTAL
+  def foo(
+    foo,
+
+    @[MyAnn]
+    &block
+  ); end
+  CRYSTAL
+
+  assert_format <<-CRYSTAL
+  def foo(
+    foo,
+
+    @[MyAnn]
+    @[MyAnn]
+    & : Nil -> Nil
+  ); end
+  CRYSTAL
+
+  assert_format <<-BEFORE, <<-AFTER
+  def foo(
+     @[MyAnn]   bar
+  ); end
+  BEFORE
+  def foo(
+    @[MyAnn] bar
+  ); end
+  AFTER
+
+  assert_format <<-CRYSTAL
+  def foo(
+    @[MyAnn]
+    bar
+  ); end
+  CRYSTAL
+
+  assert_format <<-CRYSTAL
+  def foo(
+    @[MyAnn]
+    @[MyAnn]
+    bar
+  ); end
+  CRYSTAL
+
+  assert_format <<-CRYSTAL
+  def foo(
+    @[MyAnn]
+    @[MyAnn]
+    bar,
+    @[MyAnn] baz
+  ); end
+  CRYSTAL
+
+  assert_format <<-CRYSTAL
+  def foo(
+    @[MyAnn]
+    @[MyAnn]
+    bar,
+
+    @[MyAnn] baz
+  ); end
+  CRYSTAL
+
+  assert_format <<-BEFORE, <<-AFTER
+  def foo(
+     @[MyAnn]
+   bar
+  ); end
+  BEFORE
+  def foo(
+    @[MyAnn]
+    bar
+  ); end
+  AFTER
+
+  assert_format <<-BEFORE, <<-AFTER
+  def foo(
+     @[MyAnn]    
+   bar
+  ); end
+  BEFORE
+  def foo(
+    @[MyAnn]
+    bar
+  ); end
+  AFTER
+
+  assert_format <<-BEFORE
+  def foo(
+    @[MyAnn]
+    @[MyAnn]
+    bar,
+    @[MyAnn] @[MyAnn] baz,
+    @[MyAnn]
+    @[MyAnn]
+    biz
+  ); end
+  BEFORE
+
+  assert_format <<-BEFORE
+  def foo(
+    @[MyAnn]
+    @[MyAnn]
+    bar,
+
+    @[MyAnn] @[MyAnn] baz,
+
+    @[MyAnn]
+    @[MyAnn]
+    biz
+  ); end
+  BEFORE
+
+  assert_format <<-BEFORE, <<-AFTER
+  def foo(
+    @[MyAnn]  
+    @[MyAnn]  
+    bar,
+
+    @[MyAnn]  @[MyAnn]  baz,
+
+    @[MyAnn]
+
+    @[MyAnn]
+
+    biz
+  ); end
+  BEFORE
+  def foo(
+    @[MyAnn]
+    @[MyAnn]
+    bar,
+
+    @[MyAnn] @[MyAnn] baz,
+
+    @[MyAnn]
+    @[MyAnn]
+    biz
+  ); end
+  AFTER
+
   assert_format "loop do\n  1\nrescue\n  2\nend"
   assert_format "loop do\n  1\n  loop do\n    2\n  rescue\n    3\n  end\n  4\nend"
 
diff --git a/src/compiler/crystal/tools/formatter.cr b/src/compiler/crystal/tools/formatter.cr
index 74a5577485bf..0637207a9f4d 100644
--- a/src/compiler/crystal/tools/formatter.cr
+++ b/src/compiler/crystal/tools/formatter.cr
@@ -1548,6 +1548,8 @@ module Crystal
             next if arg.external_name.empty? # skip empty splat argument.
           end
 
+          format_parameter_annotations(arg)
+
           arg.accept self
           to_skip += 1 if @last_arg_is_skip
         end
@@ -1565,6 +1567,7 @@ module Crystal
 
       if block_arg
         wrote_newline = format_def_arg(wrote_newline, false) do
+          format_parameter_annotations(block_arg)
           write_token :OP_AMP
           skip_space_or_newline
 
@@ -1591,6 +1594,31 @@ module Crystal
       to_skip
     end
 
+    private def format_parameter_annotations(node)
+      return unless (anns = node.parsed_annotations)
+
+      anns.each do |ann|
+        ann.accept self
+
+        skip_space
+
+        if @token.type.newline?
+          write_line
+          write_indent
+        else
+          write " "
+        end
+
+        skip_space_or_newline
+      end
+
+      if @token.type.newline?
+        skip_space_or_newline
+        write_line
+        write_indent
+      end
+    end
+
     def format_def_arg(wrote_newline, has_more)
       write_indent if wrote_newline