diff --git a/CHANGELOG.md b/CHANGELOG.md
index 363ed43dd51a..a12ef2ad3048 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -51,6 +51,8 @@ Main (unreleased)
 
 - Updated dependency to add support for Go 1.22 (@stefanb)
 
+- Use Go 1.21.6 for builds. (@hainenber)
+
 v0.39.0 (2024-01-09)
 --------------------
 
diff --git a/build-image/Dockerfile b/build-image/Dockerfile
index eeea8fdce018..bf8eb01dc846 100644
--- a/build-image/Dockerfile
+++ b/build-image/Dockerfile
@@ -23,7 +23,7 @@ FROM alpine:3.17 as helm
 RUN apk add --no-cache helm
 
 # Dependency: Go and Go dependencies
-FROM golang:1.21.4-bullseye as golang
+FROM golang:1.21.6-bullseye as golang
 
 # Keep in sync with cmd/grafana-agent-operator/DEVELOPERS.md
 ENV CONTROLLER_GEN_VERSION v0.9.2
diff --git a/build-image/windows/Dockerfile b/build-image/windows/Dockerfile
index 6664d8928e82..26cc62c445be 100644
--- a/build-image/windows/Dockerfile
+++ b/build-image/windows/Dockerfile
@@ -1,4 +1,4 @@
-FROM library/golang:1.21.4-windowsservercore-1809
+FROM library/golang:1.21.6-windowsservercore-1809
 
 SHELL ["powershell", "-command"]
 
diff --git a/go.mod b/go.mod
index c3976ceb0790..2bfcd7cdaea6 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/grafana/agent
 
-go 1.21.0
+go 1.21.6
 
 require (
 	cloud.google.com/go/pubsub v1.33.0