diff --git a/Cargo.lock b/Cargo.lock
index e2241b647309f4..fb56e9b0a46bc4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -608,15 +608,6 @@ dependencies = [
  "crypto-common",
 ]
 
-[[package]]
-name = "directories"
-version = "4.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f51c5d4ddabd36886dd3e1438cb358cdcb0d7c499cb99cb4ac2e38e18b5cb210"
-dependencies = [
- "dirs-sys",
-]
-
 [[package]]
 name = "dirs"
 version = "4.0.0"
@@ -2007,7 +1998,6 @@ dependencies = [
  "similar",
  "strum",
  "textwrap",
- "update-informer",
  "ureq",
  "walkdir",
 ]
@@ -2758,19 +2748,6 @@ version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a156c684c91ea7d62626509bce3cb4e1d9ed5c4d978f7b4352658f96a4c26b4a"
 
-[[package]]
-name = "update-informer"
-version = "0.6.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "152ff185ca29f7f487c51ca785b0f1d85970c4581f4cdd12ed499227890200f5"
-dependencies = [
- "directories",
- "semver",
- "serde",
- "serde_json",
- "ureq",
-]
-
 [[package]]
 name = "ureq"
 version = "2.6.2"
@@ -2782,8 +2759,6 @@ dependencies = [
  "log",
  "once_cell",
  "rustls",
- "serde",
- "serde_json",
  "url",
  "webpki",
  "webpki-roots",
diff --git a/ruff_cli/Cargo.toml b/ruff_cli/Cargo.toml
index dddccdaa5cce0d..fdfe62eaae0de9 100644
--- a/ruff_cli/Cargo.toml
+++ b/ruff_cli/Cargo.toml
@@ -51,7 +51,6 @@ serde = { version = "1.0.147", features = ["derive"] }
 serde_json = { version = "1.0.87" }
 similar = { version = "2.2.1" }
 textwrap = { version = "0.16.0" }
-update-informer = { version = "0.6.0", default-features = false, features = ["pypi"], optional = true }
 walkdir = { version = "2.3.2" }
 strum = "0.24.1"
 
@@ -60,10 +59,6 @@ assert_cmd = { version = "2.0.4" }
 strum = { version = "0.24.1" }
 ureq = { version = "2.5.0", features = [] }
 
-[features]
-default = ["update-informer"]
-update-informer = ["dep:update-informer"]
-
 [package.metadata.maturin]
 name = "ruff"
 # Setting the name here is necessary for maturin to include the package in its builds.
diff --git a/ruff_cli/src/args.rs b/ruff_cli/src/args.rs
index 2b6c98f7b1b1e0..278321e86e4de6 100644
--- a/ruff_cli/src/args.rs
+++ b/ruff_cli/src/args.rs
@@ -209,7 +209,7 @@ pub struct CheckArgs {
     /// Exit with status code "0", even upon detecting lint violations.
     #[arg(short, long, help_heading = "Miscellaneous")]
     pub exit_zero: bool,
-    /// Enable or disable automatic update checks.
+    /// (Deprecated, does nothing.) Enable or disable automatic update checks.
     #[arg(
         long,
         overrides_with("no_update_check"),
diff --git a/ruff_cli/src/main.rs b/ruff_cli/src/main.rs
index 96877f7933e80e..50e3f8957d3c47 100644
--- a/ruff_cli/src/main.rs
+++ b/ruff_cli/src/main.rs
@@ -31,8 +31,6 @@ mod diagnostics;
 mod iterators;
 mod printer;
 mod resolve;
-#[cfg(all(feature = "update-informer"))]
-pub mod updates;
 
 fn inner_main() -> Result<ExitCode> {
     let mut args: Vec<_> = std::env::args_os().collect();
@@ -258,14 +256,10 @@ fn check(args: CheckArgs, log_level: LogLevel) -> Result<ExitCode> {
             }
         }
 
-        // Check for updates if we're in a non-silent log level.
-        #[cfg(feature = "update-informer")]
-        if update_check
-            && !is_stdin
-            && log_level >= LogLevel::Default
-            && atty::is(atty::Stream::Stdout)
-        {
-            drop(updates::check_for_updates());
+        if update_check {
+            warn_user_once!(
+                "update-check has been removed; setting it will be an error in a future version."
+            );
         }
 
         if !cli.exit_zero {
diff --git a/ruff_cli/src/updates.rs b/ruff_cli/src/updates.rs
deleted file mode 100644
index 41fa51f46e3b26..00000000000000
--- a/ruff_cli/src/updates.rs
+++ /dev/null
@@ -1,75 +0,0 @@
-use std::fs::{create_dir_all, read_to_string, File};
-use std::io::Write;
-use std::path::{Path, PathBuf};
-
-use anyhow::Result;
-use colored::Colorize;
-
-const CARGO_PKG_NAME: &str = env!("CARGO_PKG_NAME");
-const CARGO_PKG_VERSION: &str = env!("CARGO_PKG_VERSION");
-
-fn cache_dir() -> &'static str {
-    "./.ruff_cache"
-}
-
-fn file_path() -> PathBuf {
-    Path::new(cache_dir()).join(".update-informer")
-}
-
-/// Get the "latest" version for which the user has been informed.
-fn get_latest() -> Result<Option<String>> {
-    let path = file_path();
-    if path.exists() {
-        Ok(Some(read_to_string(path)?.trim().to_string()))
-    } else {
-        Ok(None)
-    }
-}
-
-/// Set the "latest" version for which the user has been informed.
-fn set_latest(version: &str) -> Result<()> {
-    create_dir_all(cache_dir())?;
-    let path = file_path();
-    let mut file = File::create(path)?;
-    file.write_all(version.trim().as_bytes())?;
-    Ok(())
-}
-
-/// Update the user if a newer version is available.
-pub fn check_for_updates() -> Result<()> {
-    use update_informer::{registry, Check};
-
-    let informer = update_informer::new(registry::PyPI, CARGO_PKG_NAME, CARGO_PKG_VERSION);
-
-    if let Some(new_version) = informer
-        .check_version()
-        .ok()
-        .flatten()
-        .map(|version| version.to_string())
-    {
-        // If we've already notified the user about this version, return early.
-        if let Some(latest_version) = get_latest()? {
-            if latest_version == new_version {
-                return Ok(());
-            }
-        }
-        set_latest(&new_version)?;
-
-        let msg = format!(
-            "A new version of {pkg_name} is available: v{pkg_version} -> {new_version}",
-            pkg_name = CARGO_PKG_NAME.italic().cyan(),
-            pkg_version = CARGO_PKG_VERSION,
-            new_version = new_version.green()
-        );
-
-        let cmd = format!(
-            "Run to update: {cmd} {pkg_name}",
-            cmd = "pip3 install --upgrade".green(),
-            pkg_name = CARGO_PKG_NAME.green()
-        );
-
-        println!("\n{msg}\n{cmd}");
-    }
-
-    Ok(())
-}