diff --git a/CHANGELOG.md b/CHANGELOG.md
index 01e159abfc..8081249bd0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,7 @@
 * [#2408](https://github.com/ruby-grape/grape/pull/2408): Fix params method redefined warnings - [@ericproulx](https://github.com/ericproulx).
 * [#2410](https://github.com/ruby-grape/grape/pull/2410): Gem deprecations will raise a DeprecationWarning in specs - [@ericproulx](https://github.com/ericproulx).
 * [#2389](https://github.com/ruby-grape/grape/pull/2389): Remove rack-accept dependency - [@ericproulx](https://github.com/ericproulx).
+* [#2425](https://github.com/ruby-grape/grape/pull/2425): Replace `{}` with `Rack::Header` (for rack 3.0 and greater) or Rack::Utils::HeaderHash` (for rack less than 3.0) in Grape::DSL::Headers - [@dhruvCW](https://github.com/dhruvCW).
 * Your contribution here.
 
 #### Fixes
diff --git a/lib/grape/dsl/headers.rb b/lib/grape/dsl/headers.rb
index b84c4efe4d..962624774e 100644
--- a/lib/grape/dsl/headers.rb
+++ b/lib/grape/dsl/headers.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require 'grape/util/header'
 module Grape
   module DSL
     module Headers
@@ -12,7 +13,7 @@ def header(key = nil, val = nil)
         if key
           val ? header[key.to_s] = val : header.delete(key.to_s)
         else
-          @header ||= {}
+          @header ||= Util::Header.new
         end
       end
       alias headers header
diff --git a/lib/grape/endpoint.rb b/lib/grape/endpoint.rb
index 121b1c4d68..389bf4b63b 100644
--- a/lib/grape/endpoint.rb
+++ b/lib/grape/endpoint.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'grape/util/header'
+
 module Grape
   # An Endpoint is the proxy scope in which all routing
   # blocks are executed. In other words, any methods
@@ -238,7 +240,7 @@ def equals?(e)
 
     def run
       ActiveSupport::Notifications.instrument('endpoint_run.grape', endpoint: self, env: env) do
-        @header = {}
+        @header = Grape::Util::Header.new
         @request = Grape::Request.new(env, build_params_with: namespace_inheritable(:build_params_with))
         @params = @request.params
         @headers = @request.headers
diff --git a/lib/grape/request.rb b/lib/grape/request.rb
index c907f0b4ab..da020b6ba4 100644
--- a/lib/grape/request.rb
+++ b/lib/grape/request.rb
@@ -46,14 +46,8 @@ def build_headers
       end
     end
 
-    if Grape.lowercase_headers?
-      def transform_header(header)
-        -header[5..].tr('_', '-').downcase
-      end
-    else
-      def transform_header(header)
-        -header[5..].split('_').map(&:capitalize).join('-')
-      end
+    def transform_header(header)
+      -header[5..].tr('_', '-').downcase
     end
   end
 end
diff --git a/lib/grape/util/header.rb b/lib/grape/util/header.rb
new file mode 100644
index 0000000000..b3aee99adb
--- /dev/null
+++ b/lib/grape/util/header.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module Grape
+  module Util
+    begin
+      # For `Rack::Headers` (Rack 3+):
+      require 'rack/headers'
+      Header = Rack::Headers
+    rescue LoadError
+      # For `Rack::Utils::HeaderHash`:
+      require 'rack/utils'
+      Header = Rack::Utils::HeaderHash
+    end
+  end
+end
diff --git a/spec/grape/api/custom_validations_spec.rb b/spec/grape/api/custom_validations_spec.rb
index a6b7a629c1..3b01e95baa 100644
--- a/spec/grape/api/custom_validations_spec.rb
+++ b/spec/grape/api/custom_validations_spec.rb
@@ -169,12 +169,12 @@ def validate(request)
         end
 
         def access_header
-          Grape.lowercase_headers? ? 'x-access-token' : 'X-Access-Token'
+          'x-access-token'
         end
       end
     end
     let(:app) { Rack::Builder.new(subject) }
-    let(:x_access_token_header) { Grape.lowercase_headers? ? 'x-access-token' : 'X-Access-Token' }
+    let(:x_access_token_header) { 'x-access-token' }
 
     before do
       described_class.register_validator('admin', admin_validator)
diff --git a/spec/grape/dsl/headers_spec.rb b/spec/grape/dsl/headers_spec.rb
index 9ced6304ff..154fbf82b2 100644
--- a/spec/grape/dsl/headers_spec.rb
+++ b/spec/grape/dsl/headers_spec.rb
@@ -11,8 +11,8 @@ class Dummy
       subject { HeadersSpec::Dummy.new }
 
       let(:header_data) do
-        { 'First Key' => 'First Value',
-          'Second Key' => 'Second Value' }
+        { 'first key' => 'First Value',
+          'second key' => 'Second Value' }
       end
 
       context 'when headers are set' do
@@ -23,8 +23,8 @@ class Dummy
 
           describe 'get' do
             it 'returns a specifc value' do
-              expect(subject.header['First Key']).to eq 'First Value'
-              expect(subject.header['Second Key']).to eq 'Second Value'
+              expect(subject.header['first key']).to eq 'First Value'
+              expect(subject.header['second key']).to eq 'Second Value'
             end
 
             it 'returns all set headers' do
@@ -35,15 +35,15 @@ class Dummy
 
           describe 'set' do
             it 'returns value' do
-              expect(subject.header('Third Key', 'Third Value'))
-              expect(subject.header['Third Key']).to eq 'Third Value'
+              expect(subject.header('third key', 'Third Value'))
+              expect(subject.header['third key']).to eq 'Third Value'
             end
           end
 
           describe 'delete' do
             it 'deletes a header key-value pair' do
-              expect(subject.header('First Key')).to eq header_data['First Key']
-              expect(subject.header).not_to have_key('First Key')
+              expect(subject.header('first key')).to eq header_data['first key']
+              expect(subject.header).not_to have_key('first key')
             end
           end
         end
@@ -52,8 +52,8 @@ class Dummy
       context 'when no headers are set' do
         describe '#header' do
           it 'returns nil' do
-            expect(subject.header['First Key']).to be_nil
-            expect(subject.header('First Key')).to be_nil
+            expect(subject.header['first key']).to be_nil
+            expect(subject.header('first key')).to be_nil
           end
         end
       end
diff --git a/spec/grape/endpoint_spec.rb b/spec/grape/endpoint_spec.rb
index d8e88aeb10..a1a10d2441 100644
--- a/spec/grape/endpoint_spec.rb
+++ b/spec/grape/endpoint_spec.rb
@@ -146,7 +146,7 @@ def app
 
     it 'includes additional request headers' do
       get '/headers', nil, 'HTTP_X_GRAPE_CLIENT' => '1'
-      x_grape_client_header = Grape.lowercase_headers? ? 'x-grape-client' : 'X-Grape-Client'
+      x_grape_client_header = 'x-grape-client'
       expect(JSON.parse(last_response.body)[x_grape_client_header]).to eq('1')
     end
 
@@ -154,7 +154,7 @@ def app
       env = Rack::MockRequest.env_for('/headers')
       env[:HTTP_SYMBOL_HEADER] = 'Goliath passes symbols'
       body = read_chunks(subject.call(env)[2]).join
-      symbol_header = Grape.lowercase_headers? ? 'symbol-header' : 'Symbol-Header'
+      symbol_header = 'symbol-header'
       expect(JSON.parse(body)[symbol_header]).to eq('Goliath passes symbols')
     end
   end
diff --git a/spec/grape/request_spec.rb b/spec/grape/request_spec.rb
index b84b6dffdc..eaf9a6ac97 100644
--- a/spec/grape/request_spec.rb
+++ b/spec/grape/request_spec.rb
@@ -90,7 +90,7 @@ module Grape
           }
         end
         let(:x_grape_is_cool_header) do
-          Grape.lowercase_headers? ? 'x-grape-is-cool' : 'X-Grape-Is-Cool'
+          'x-grape-is-cool'
         end
 
         it 'cuts HTTP_ prefix and capitalizes header name words' do
@@ -120,7 +120,7 @@ module Grape
           default_env.merge(request_headers)
         end
         let(:grape_likes_symbolic_header) do
-          Grape.lowercase_headers? ? 'grape-likes-symbolic' : 'Grape-Likes-Symbolic'
+          'grape-likes-symbolic'
         end
 
         it 'converts them to string' do