diff --git a/src/install/PackageManager/PackageManagerLifecycle.rs b/src/install/PackageManager/PackageManagerLifecycle.rs
index 730d18f94fa4..561a8daf9ceb 100644
--- a/src/install/PackageManager/PackageManagerLifecycle.rs
+++ b/src/install/PackageManager/PackageManagerLifecycle.rs
@@ -34,7 +34,12 @@ pub struct LifecycleScriptTimeLog {
     list: Vec<LifecycleScriptTimeLogEntry>,
 }
 
-pub struct LifecycleScriptTimeLogEntry {}
+pub struct LifecycleScriptTimeLogEntry {
+    pub(crate) package_name: Box<[u8]>,
+    pub(crate) script_id: u8,
+    /// nanoseconds
+    pub(crate) duration: u64,
+}
 
 impl LifecycleScriptTimeLog {
     pub(crate) fn append_concurrent(&mut self, entry: LifecycleScriptTimeLogEntry) {
@@ -42,6 +47,28 @@ impl LifecycleScriptTimeLog {
         self.list.push(entry);
         self.mutex.unlock();
     }
+
+    pub(crate) fn print_and_clear(&mut self) {
+        #[cfg(debug_assertions)]
+        {
+            assert!(
+                self.mutex.try_lock(),
+                "LifecycleScriptTimeLog.print is not intended to be thread-safe"
+            );
+            self.mutex.unlock();
+        }
+
+        if let Some(longest) = self.list.iter().max_by_key(|e| e.duration) {
+            bun_core::warn!(
+                "{}'s {} script took {}",
+                BStr::new(&longest.package_name),
+                lockfile::Scripts::NAMES[longest.script_id as usize],
+                bun_fmt::fmt_duration_one_decimal(longest.duration),
+            );
+            Output::flush();
+        }
+        self.list.clear();
+    }
 }
 
 impl PackageManager {
diff --git a/src/install/PackageManager/install_with_manager.rs b/src/install/PackageManager/install_with_manager.rs
index a06d651a152c..06b82376bf1c 100644
--- a/src/install/PackageManager/install_with_manager.rs
+++ b/src/install/PackageManager/install_with_manager.rs
@@ -1034,6 +1034,8 @@ fn print_install_summary(
     if this.options.do_.summary() {
         print_summary_tree(this, install_summary, log_level)?;
 
+        this.lifecycle_script_time_log.print_and_clear();
+
         if !did_meta_hash_change {
             this.summary.remove = 0;
             this.summary.add = 0;
diff --git a/src/install/lifecycle_script_runner.rs b/src/install/lifecycle_script_runner.rs
index c323f1bb12fa..ccb57a767d9b 100644
--- a/src/install/lifecycle_script_runner.rs
+++ b/src/install/lifecycle_script_runner.rs
@@ -676,6 +676,7 @@ impl<'a> LifecycleScriptSubprocess<'a> {
             (*this).remaining_fds = 0;
             (*this).started_at =
                 bun_core::Timespec::now(bun_core::TimespecMockMode::AllowMockedTime).ns();
+            (*this).timer = Some(Timer::start());
             // Store the allocation-rooted `this` in the intrusive heap — not a `&mut self`
             // reborrow, whose SB tag would be invalidated by the field accesses below.
             (*manager)
@@ -909,14 +910,20 @@ impl<'a> LifecycleScriptSubprocess<'a> {
                     }
                 }
 
-                if let Some(nanos) = maybe_duration {
-                    if nanos > MIN_MILLISECONDS_TO_LOG * bun_core::time::NS_PER_MS {
-                        let entry = LifecycleScriptTimeLogEntry {};
-                        // SAFETY: see [`Self::manager_mut`].
-                        unsafe { self.manager_mut() }
-                            .lifecycle_script_time_log
-                            .append_concurrent(entry);
-                    }
+                // Foreground (root-package) scripts were already echoed live; warn only for background deps.
+                if !self.foreground
+                    && let Some(nanos) = maybe_duration
+                    && nanos > MIN_MILLISECONDS_TO_LOG * bun_core::time::NS_PER_MS
+                {
+                    let entry = LifecycleScriptTimeLogEntry {
+                        package_name: self.package_name.clone(),
+                        script_id: self.current_script_index,
+                        duration: nanos,
+                    };
+                    // SAFETY: see [`Self::manager_mut`].
+                    unsafe { self.manager_mut() }
+                        .lifecycle_script_time_log
+                        .append_concurrent(entry);
                 }
 
                 if let Some(ctx) = &self.ctx {
diff --git a/test/cli/install/bun-install-lifecycle-scripts.test.ts b/test/cli/install/bun-install-lifecycle-scripts.test.ts
index 8123acc24bdf..f01e5274e736 100644
--- a/test/cli/install/bun-install-lifecycle-scripts.test.ts
+++ b/test/cli/install/bun-install-lifecycle-scripts.test.ts
@@ -2135,6 +2135,50 @@ for (const forceWaiterThread of isLinux ? [false, true] : [false]) {
       return dependenciesList;
     }
 
+    test("slow lifecycle script prints a warning", async () => {
+      using ctx = await setupTest();
+      const { packageDir, packageJson, env } = ctx;
+      const testEnv = forceWaiterThread ? { ...env, BUN_FEATURE_FLAG_FORCE_WAITER_THREAD: "1" } : env;
+
+      await mkdir(join(packageDir, "slow-pkg"));
+      await writeFile(
+        join(packageDir, "slow-pkg", "package.json"),
+        JSON.stringify({
+          name: "slow-pkg",
+          version: "1.0.0",
+          scripts: {
+            postinstall: `${bunExe()} -e 'Bun.sleepSync(750)'`,
+          },
+        }),
+      );
+      await writeFile(
+        packageJson,
+        JSON.stringify({
+          name: "foo",
+          version: "1.0.0",
+          dependencies: {
+            "slow-pkg": "file:./slow-pkg",
+          },
+          trustedDependencies: ["slow-pkg"],
+        }),
+      );
+
+      const { stdout, stderr, exited } = spawn({
+        cmd: [bunExe(), "install"],
+        cwd: packageDir,
+        stdout: "pipe",
+        stdin: "ignore",
+        stderr: "pipe",
+        env: testEnv,
+      });
+
+      const [err, out, exitCode] = await Promise.all([stderr.text(), stdout.text(), exited]);
+      expect(err).not.toContain("error:");
+      expect(err).toMatch(/warn: slow-pkg's postinstall script took \d/);
+      expect(out).toContain("1 package installed");
+      expect(exitCode).toBe(0);
+    });
+
     test("reach max concurrent scripts", async () => {
       using ctx = await setupTest();
       const { packageDir, packageJson, env } = ctx;
diff --git a/test/harness.ts b/test/harness.ts
index 9ee228e80515..3e9a27aaf8aa 100644
--- a/test/harness.ts
+++ b/test/harness.ts
@@ -1511,9 +1511,10 @@ export async function runBunInstall(
   return { out, err, exited };
 }
 
-// stderr with `slow filesystem` warning removed
+// stderr with timing-dependent warnings removed (debug/ASAN builds can push any
+// lifecycle script over the 500ms slow-script threshold)
 export function stderrForInstall(err: string) {
-  return err.replace(/warn: Slow filesystem.*/g, "");
+  return err.replace(/warn: Slow filesystem.*/g, "").replace(/warn: .*'s \S+ script took .*\n?\n?/g, "");
 }
 
 export async function runBunUpdate(