diff --git a/core/src/main/scala/sttp/client4/requestBuilder.scala b/core/src/main/scala/sttp/client4/requestBuilder.scala
index de46a42d3..30a99ec11 100644
--- a/core/src/main/scala/sttp/client4/requestBuilder.scala
+++ b/core/src/main/scala/sttp/client4/requestBuilder.scala
@@ -321,7 +321,8 @@ trait PartialRequestBuilder[+PR <: PartialRequestBuilder[PR, R], +R]
     * @see
     *   [[sttp.model.Encodings]]
     */
-  def compressBody(encoding: String): PR = withOptions(options.copy(compressRequestBody = Some(encoding)))
+  def compressBody(encoding: String): PR =
+    withOptions(options.copy(compressRequestBody = Some(encoding))).header(HeaderNames.ContentEncoding, encoding)
 
   /** Set the HTTP version with which this request should be sent. Supported only in a few backends. */
   def httpVersion(version: HttpVersion): PR = withOptions(options.copy(httpVersion = Some(version)))
diff --git a/core/src/test/scala/sttp/client4/RequestTests.scala b/core/src/test/scala/sttp/client4/RequestTests.scala
index 2e3c61f29..27e3536b0 100644
--- a/core/src/test/scala/sttp/client4/RequestTests.scala
+++ b/core/src/test/scala/sttp/client4/RequestTests.scala
@@ -3,6 +3,7 @@ package sttp.client4
 import sttp.model.{Header, HeaderNames, StatusCode}
 import org.scalatest.flatspec.AnyFlatSpec
 import org.scalatest.matchers.should.Matchers
+import sttp.model.Encodings
 
 class RequestTests extends AnyFlatSpec with Matchers {
 
@@ -108,4 +109,10 @@ class RequestTests extends AnyFlatSpec with Matchers {
       Header("Content-Length", "4")
     )
   }
+
+  "compressBody" should "add the content encoding header" in {
+    emptyRequest.compressBody(Encodings.Gzip).headers.toSet shouldBe Set(
+      Header(HeaderNames.ContentEncoding, Encodings.Gzip)
+    )
+  }
 }