diff --git a/packages/SwingSet/src/controller/controller.js b/packages/SwingSet/src/controller/controller.js
index 404619164f2f..ccd5249b091d 100644
--- a/packages/SwingSet/src/controller/controller.js
+++ b/packages/SwingSet/src/controller/controller.js
@@ -21,6 +21,7 @@ import { waitUntilQuiescent } from '@agoric/internal/src/lib-nodejs/waitUntilQui
 import { makeGcAndFinalize } from '@agoric/internal/src/lib-nodejs/gc-and-finalize.js';
 import { kslot, krefOf } from '@agoric/kmarshal';
 import { insistStorageAPI } from '../lib/storageAPI.js';
+import { insistCapData } from '../lib/capdata.js';
 import {
   buildKernelBundle,
   swingsetIsInitialized,
@@ -33,6 +34,10 @@ import {
 import { makeStartXSnap } from './startXSnap.js';
 import { makeStartSubprocessWorkerNode } from './startNodeSubprocess.js';
 
+/**
+ * @typedef { import('../types-internal.js').VatID } VatID
+ */
+
 const endoZipBase64Sha512Shape = harden({
   moduleFormat: 'endoZipBase64',
   endoZipBase64: M.string(harden({ stringLengthLimit: Infinity })),
@@ -440,6 +445,48 @@ export async function makeSwingsetController(
       // no emitCrankHashes here because queueToVatRoot did that
       return result;
     },
+
+    /**
+     * terminate a vat by ID
+     *
+     * This allows the host app to terminate any vat. The effect is
+     * equivalent to the holder of the vat's `adminNode` calling
+     * `E(adminNode).terminateWithFailure(reason)`, or the vat itself
+     * calling `vatPowers.exitVatWithFailure(reason)`. It accepts a
+     * reason capdata structure (use 'kser()' to build one), which
+     * will be included in rejection data for the promise available to
+     * `E(adminNode).done()`, just like the internal termination APIs.
+     * Note that no slots/krefs are allowed in 'reason' when
+     * terminating the vat externally.
+     *
+     * This is a superpower available only from the host app, not from
+     * within vats, since `vatID` is merely a string and can be forged
+     * trivially. The host app is responsible for supplying the right
+     * vatID to kill, by looking at the database or logs (note that
+     * vats do not know their own vatID, and `controller.vatNameToID`
+     * only works for static vats, not dynamic).
+     *
+     * This will cause state changes in the swing-store (specifically
+     * marking the vat as terminated, and rejection all its
+     * outstanding promises), which must be committed before they will
+     * be durable. Either call `hostStorage.commit()` immediately
+     * after calling this, or call `controller.run()` and *then*
+     * `hostStorage.commit()` as you would normally do in response to
+     * other IO or timer activity.
+     *
+     * The first `controller.run()` after this call will delete all
+     * the old vat's state at once, unless you use a `runPolicy` to
+     * rate-limit cleanups.
+     *
+     * @param {VatID} vatID
+     * @param {SwingSetCapData} reasonCD
+     */
+
+    terminateVat(vatID, reasonCD) {
+      insistCapData(reasonCD);
+      assert(reasonCD.slots.length === 0, 'no slots allowed in reason');
+      kernel.terminateVatExternally(vatID, reasonCD);
+    },
   });
 
   writeSlogObject({ type: 'kernel-init-finish' });
diff --git a/packages/SwingSet/src/kernel/kernel.js b/packages/SwingSet/src/kernel/kernel.js
index 83ca54c029aa..b1bafd52ef3b 100644
--- a/packages/SwingSet/src/kernel/kernel.js
+++ b/packages/SwingSet/src/kernel/kernel.js
@@ -2051,6 +2051,16 @@ export default function buildKernel(
     hooks[hookName] = hook;
   }
 
+  function terminateVatExternally(vatID, reasonCD) {
+    assert(started, 'must do kernel.start() before terminateVatExternally()');
+    insistCapData(reasonCD);
+    assert(reasonCD.slots.length === 0, 'no slots allowed in reason');
+    // this fires a promise when worker is dead, mostly for tests, so don't
+    // give it to external callers
+    void terminateVat(vatID, true, reasonCD);
+    console.log(`scheduled vatID ${vatID} for termination`);
+  }
+
   const kernel = harden({
     // these are meant for the controller
     installBundle,
@@ -2126,6 +2136,7 @@ export default function buildKernel(
     kpStatus,
     kpResolution,
     addDeviceHook,
+    terminateVatExternally,
   });
 
   return kernel;
diff --git a/packages/SwingSet/test/external-termination/bootstrap-external-termination.js b/packages/SwingSet/test/external-termination/bootstrap-external-termination.js
new file mode 100644
index 000000000000..70e24801a4d1
--- /dev/null
+++ b/packages/SwingSet/test/external-termination/bootstrap-external-termination.js
@@ -0,0 +1,27 @@
+import { Far, E } from '@endo/far';
+
+export function buildRootObject() {
+  let vatAdmin;
+  let bcap;
+  let root;
+  let adminNode;
+  let exitval;
+
+  return Far('root', {
+    bootstrap: async (vats, devices) => {
+      vatAdmin = await E(vats.vatAdmin).createVatAdminService(devices.vatAdmin);
+      bcap = await E(vatAdmin).getNamedBundleCap('doomed');
+      const res = await E(vatAdmin).createVat(bcap);
+      root = res.root;
+      adminNode = res.adminNode;
+      E(adminNode)
+        .done()
+        .then(
+          happy => (exitval = ['fulfill', happy]),
+          sad => (exitval = ['reject', sad]),
+        );
+    },
+    ping: async count => E(root).ping(count),
+    getExitVal: () => exitval,
+  });
+}
diff --git a/packages/SwingSet/test/external-termination/external-termination.test.js b/packages/SwingSet/test/external-termination/external-termination.test.js
new file mode 100644
index 000000000000..08c55ddc8b29
--- /dev/null
+++ b/packages/SwingSet/test/external-termination/external-termination.test.js
@@ -0,0 +1,83 @@
+// eslint-disable-next-line import/order
+import { test } from '../../tools/prepare-test-env-ava.js';
+
+import { initSwingStore } from '@agoric/swing-store';
+import { kser, kunser } from '@agoric/kmarshal';
+import { initializeSwingset, makeSwingsetController } from '../../src/index.js';
+
+const bfile = name => new URL(name, import.meta.url).pathname;
+
+const testExternalTermination = async (t, defaultManagerType) => {
+  /** @type {SwingSetConfig} */
+  const config = {
+    defaultManagerType,
+    bootstrap: 'bootstrap',
+    vats: {
+      bootstrap: { sourceSpec: bfile('./bootstrap-external-termination.js') },
+    },
+    bundles: {
+      doomed: { sourceSpec: bfile('./vat-doomed.js') },
+    },
+  };
+
+  const kernelStorage = initSwingStore().kernelStorage;
+  await initializeSwingset(config, [], kernelStorage);
+  const c = await makeSwingsetController(kernelStorage);
+  t.teardown(c.shutdown);
+  c.pinVatRoot('bootstrap');
+  await c.run();
+
+  // vat-doomed should now be running. We casually assume the new vat
+  // has the last ID
+  const vatIDs = c.dump().vatTables.map(vt => vt.vatID);
+  const vatID = vatIDs[vatIDs.length - 1];
+
+  {
+    const kpid = c.queueToVatRoot('bootstrap', 'ping', [1]);
+    await c.run();
+    t.is(kunser(c.kpResolution(kpid)), 1);
+  }
+  {
+    const kpid = c.queueToVatRoot('bootstrap', 'getExitVal');
+    await c.run();
+    t.is(kunser(c.kpResolution(kpid)), undefined);
+  }
+
+  // The "vat has been terminated" flags are set synchronously during
+  // c.terminateVat(), as well as all the vat's promises being
+  // rejected. The deletion of state happens during the first cleanup
+  // crank, which (since we aren't limiting it with a runPolicy)
+  // cleans to completion during this c.run()
+
+  c.terminateVat(vatID, kser('doom!'));
+  await c.run();
+
+  t.false(
+    c
+      .dump()
+      .vatTables.map(vt => vt.vatID)
+      .includes(vatID),
+  );
+
+  {
+    // this provokes noise: liveslots logs one RemoteError
+    const kpid = c.queueToVatRoot('bootstrap', 'ping', [1]);
+    await c.run();
+    t.is(c.kpStatus(kpid), 'rejected');
+    t.deepEqual(kunser(c.kpResolution(kpid)), Error('vat terminated'));
+  }
+
+  {
+    const kpid = c.queueToVatRoot('bootstrap', 'getExitVal');
+    await c.run();
+    t.deepEqual(kunser(c.kpResolution(kpid)), ['reject', 'doom!']);
+  }
+};
+
+test('external termination: local worker', async t => {
+  await testExternalTermination(t, 'local');
+});
+
+test('external termination: xsnap worker', async t => {
+  await testExternalTermination(t, 'xsnap');
+});
diff --git a/packages/SwingSet/test/external-termination/vat-doomed.js b/packages/SwingSet/test/external-termination/vat-doomed.js
new file mode 100644
index 000000000000..c2a1e079f51b
--- /dev/null
+++ b/packages/SwingSet/test/external-termination/vat-doomed.js
@@ -0,0 +1,7 @@
+import { Far } from '@endo/far';
+
+export function buildRootObject() {
+  return Far('doomed', {
+    ping: count => count,
+  });
+}