diff --git a/Dockerfile b/Dockerfile
index 71c708e0..d63c7bd3 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,7 +8,7 @@ FROM debian:trixie-slim
 ARG TARGETPLATFORM
 
 # Keep in sync with the go directive in go/helper/go.mod.
-ARG GO_VERSION=1.27.1
+ARG GO_VERSION=1.27.3
 
 RUN apt-get update \
 	&& apt-get install -y --no-install-recommends ca-certificates curl \
diff --git a/README.md b/README.md
index 552138a9..8c9bbd04 100644
--- a/README.md
+++ b/README.md
@@ -18,7 +18,7 @@ brew install oullin/fmtkit/fmtkit
 # Docker (linux/amd64, linux/arm64; includes Go for go vet)
 docker run --rm -u "$(id -u):$(id -g)" -v "$PWD:/work" ghcr.io/oullin/fmtkit:latest check --all
 
-# From source (Rust 1.96+, Go 1.27.1)
+# From source (Rust 1.96+, Go 1.27.3)
 git clone https://github.com/oullin/fmtkit.git && cd fmtkit && make build
 ```
 
@@ -220,7 +220,7 @@ fmtkit schema=2 mode=check result=fail files=2 changed=2 violations=5 lint=5 com
 
 ## Development
 
-Needs Rust 1.96+, Go 1.27.1, and Bash. Build output goes to `storage/`.
+Needs Rust 1.96+, Go 1.27.3, and Bash. Build output goes to `storage/`.
 
 | Target        | What it does                                          |
 | ------------- | ----------------------------------------------------- |
diff --git a/go/helper/go.mod b/go/helper/go.mod
index 6e1dc910..e51830e9 100644
--- a/go/helper/go.mod
+++ b/go/helper/go.mod
@@ -1,6 +1,6 @@
 module go.ollin.sh/fmtkit/go/helper
 
-go 1.27.1
+go 1.27.3
 
 require (
 	github.com/fzipp/gocyclo v0.6.0