diff --git a/lib/grape/dsl/inside_route.rb b/lib/grape/dsl/inside_route.rb
index cc56a72d21..bcfd3e84c8 100644
--- a/lib/grape/dsl/inside_route.rb
+++ b/lib/grape/dsl/inside_route.rb
@@ -329,7 +329,7 @@ def stream(value = nil)
         return if value.nil? && @stream.nil?
 
         header Rack::CONTENT_LENGTH, nil
-        header Rack::TRANSFER_ENCODING, nil
+        header Grape::Http::Headers::TRANSFER_ENCODING, nil
         header Rack::CACHE_CONTROL, 'no-cache' # Skips ETag generation (reading the response up front)
         if value.is_a?(String)
           file_body = Grape::ServeStream::FileBody.new(value)
diff --git a/lib/grape/http/headers.rb b/lib/grape/http/headers.rb
index a9cd7d1ee5..a7e5984f75 100644
--- a/lib/grape/http/headers.rb
+++ b/lib/grape/http/headers.rb
@@ -12,13 +12,15 @@ module Headers
       QUERY_STRING    = 'QUERY_STRING'
 
       if Grape.lowercase_headers?
-        ALLOW     = 'allow'
-        LOCATION  = 'location'
-        X_CASCADE = 'x-cascade'
+        ALLOW             = 'allow'
+        LOCATION          = 'location'
+        TRANSFER_ENCODING = 'transfer-encoding'
+        X_CASCADE         = 'x-cascade'
       else
-        ALLOW     = 'Allow'
-        LOCATION  = 'Location'
-        X_CASCADE = 'X-Cascade'
+        ALLOW             = 'Allow'
+        LOCATION          = 'Location'
+        TRANSFER_ENCODING = 'Transfer-Encoding'
+        X_CASCADE         = 'X-Cascade'
       end
 
       GET     = 'GET'
diff --git a/spec/grape/api_spec.rb b/spec/grape/api_spec.rb
index 39dc9df4d4..161b561cbb 100644
--- a/spec/grape/api_spec.rb
+++ b/spec/grape/api_spec.rb
@@ -1260,7 +1260,7 @@ class DummyFormatClass
       expect(last_response.headers[Rack::CONTENT_TYPE]).to eq('text/plain')
       expect(last_response.headers[Rack::CONTENT_LENGTH]).to be_nil
       expect(last_response.headers[Rack::CACHE_CONTROL]).to eq('no-cache')
-      expect(last_response.headers[Rack::TRANSFER_ENCODING]).to eq('chunked')
+      expect(last_response.headers[Grape::Http::Headers::TRANSFER_ENCODING]).to eq('chunked')
 
       expect(last_response.body).to eq("c\r\nThis is some\r\nd\r\n file content\r\n0\r\n\r\n")
     end
diff --git a/spec/grape/dsl/inside_route_spec.rb b/spec/grape/dsl/inside_route_spec.rb
index 551a3ca193..931382e48c 100644
--- a/spec/grape/dsl/inside_route_spec.rb
+++ b/spec/grape/dsl/inside_route_spec.rb
@@ -265,7 +265,7 @@ def initialize
         before do
           subject.header Rack::CACHE_CONTROL, 'cache'
           subject.header Rack::CONTENT_LENGTH, 123
-          subject.header Rack::TRANSFER_ENCODING, 'base64'
+          subject.header Grape::Http::Headers::TRANSFER_ENCODING, 'base64'
         end
 
         it 'sends no deprecation warnings' do
@@ -295,7 +295,7 @@ def initialize
         it 'does not change the Transfer-Encoding header' do
           subject.sendfile file_path
 
-          expect(subject.header[Rack::TRANSFER_ENCODING]).to eq 'base64'
+          expect(subject.header[Grape::Http::Headers::TRANSFER_ENCODING]).to eq 'base64'
         end
       end
 
@@ -326,7 +326,7 @@ def initialize
         before do
           subject.header Rack::CACHE_CONTROL, 'cache'
           subject.header Rack::CONTENT_LENGTH, 123
-          subject.header Rack::TRANSFER_ENCODING, 'base64'
+          subject.header Grape::Http::Headers::TRANSFER_ENCODING, 'base64'
         end
 
         it 'emits no deprecation warnings' do
@@ -362,7 +362,7 @@ def initialize
         it 'sets Transfer-Encoding header to nil' do
           subject.stream file_path
 
-          expect(subject.header[Rack::TRANSFER_ENCODING]).to be_nil
+          expect(subject.header[Grape::Http::Headers::TRANSFER_ENCODING]).to be_nil
         end
       end
 
@@ -376,7 +376,7 @@ def initialize
         before do
           subject.header Rack::CACHE_CONTROL, 'cache'
           subject.header Rack::CONTENT_LENGTH, 123
-          subject.header Rack::TRANSFER_ENCODING, 'base64'
+          subject.header Grape::Http::Headers::TRANSFER_ENCODING, 'base64'
         end
 
         it 'emits no deprecation warnings' do
@@ -406,7 +406,7 @@ def initialize
         it 'sets Transfer-Encoding header to nil' do
           subject.stream stream_object
 
-          expect(subject.header[Rack::TRANSFER_ENCODING]).to be_nil
+          expect(subject.header[Grape::Http::Headers::TRANSFER_ENCODING]).to be_nil
         end
       end
 
diff --git a/spec/integration/rack/v2/headers_spec.rb b/spec/integration/rack/v2/headers_spec.rb
index 5a915f63a2..4819f21dc1 100644
--- a/spec/integration/rack/v2/headers_spec.rb
+++ b/spec/integration/rack/v2/headers_spec.rb
@@ -3,5 +3,6 @@
 describe Grape::Http::Headers do
   it { expect(described_class::ALLOW).to eq('Allow') }
   it { expect(described_class::LOCATION).to eq('Location') }
+  it { expect(described_class::TRANSFER_ENCODING).to eq('Transfer-Encoding') }
   it { expect(described_class::X_CASCADE).to eq('X-Cascade') }
 end
diff --git a/spec/integration/rack/v3/headers_spec.rb b/spec/integration/rack/v3/headers_spec.rb
index 0796b23616..3be2c1e28b 100644
--- a/spec/integration/rack/v3/headers_spec.rb
+++ b/spec/integration/rack/v3/headers_spec.rb
@@ -3,5 +3,6 @@
 describe Grape::Http::Headers do
   it { expect(described_class::ALLOW).to eq('allow') }
   it { expect(described_class::LOCATION).to eq('location') }
+  it { expect(described_class::TRANSFER_ENCODING).to eq('transfer-encoding') }
   it { expect(described_class::X_CASCADE).to eq('x-cascade') }
 end