diff --git a/CHANGELOG.md b/CHANGELOG.md
index ca61b7caae47..bd11991dd4d5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,8 +7,9 @@ This document contains a historical list of changes between releases. Only
 changes that impact end-user behavior are listed; changes to documentation or
 internal API changes are not present.
 
-Main (unreleased)
------------------
+
+v0.40.0-rc.0 (2024-02-22)
+-------------------------
 
 ### Breaking changes
 
diff --git a/docs/sources/_index.md b/docs/sources/_index.md
index a902be317bab..f990dff3980b 100644
--- a/docs/sources/_index.md
+++ b/docs/sources/_index.md
@@ -9,7 +9,7 @@ title: Grafana Agent
 description: Grafana Agent is a flexible, performant, vendor-neutral, telemetry collector
 weight: 350
 cascade:
-  AGENT_RELEASE: v0.39.2
+  AGENT_RELEASE: v0.40.0-rc.0
   OTEL_VERSION: v0.87.0
 ---
 
diff --git a/pkg/operator/defaults.go b/pkg/operator/defaults.go
index 25e4e05e986d..532c2bbbffdc 100644
--- a/pkg/operator/defaults.go
+++ b/pkg/operator/defaults.go
@@ -2,7 +2,7 @@ package operator
 
 // Supported versions of the Grafana Agent.
 var (
-	DefaultAgentVersion   = "v0.39.2"
+	DefaultAgentVersion   = "v0.40.0-rc.0"
 	DefaultAgentBaseImage = "grafana/agent"
 	DefaultAgentImage     = DefaultAgentBaseImage + ":" + DefaultAgentVersion
 )
diff --git a/tools/gen-versioned-files/agent-version.txt b/tools/gen-versioned-files/agent-version.txt
index 76b2d23e8697..960798e47290 100644
--- a/tools/gen-versioned-files/agent-version.txt
+++ b/tools/gen-versioned-files/agent-version.txt
@@ -1 +1 @@
-v0.39.2
\ No newline at end of file
+v0.40.0-rc.0
\ No newline at end of file