diff --git a/cmd/zpool/zpool_main.c b/cmd/zpool/zpool_main.c
index bfef6fc43285..b40af9629ac7 100644
--- a/cmd/zpool/zpool_main.c
+++ b/cmd/zpool/zpool_main.c
@@ -397,7 +397,7 @@ get_usage(zpool_help_t idx)
 	case HELP_REOPEN:
 		return (gettext("\treopen [-n] <pool>\n"));
 	case HELP_INITIALIZE:
-		return (gettext("\tinitialize [-c | -s] [-w] <pool> "
+		return (gettext("\tinitialize [-c | -s | -u] [-w] <pool> "
 		    "[<device> ...]\n"));
 	case HELP_SCRUB:
 		return (gettext("\tscrub [-s | -p] [-w] <pool> ...\n"));
@@ -552,12 +552,13 @@ usage(boolean_t requested)
 }
 
 /*
- * zpool initialize [-c | -s] [-w] <pool> [<vdev> ...]
+ * zpool initialize [-c | -s | -u] [-w] <pool> [<vdev> ...]
  * Initialize all unused blocks in the specified vdevs, or all vdevs in the pool
  * if none specified.
  *
  *	-c	Cancel. Ends active initializing.
  *	-s	Suspend. Initializing can then be restarted with no flags.
+ *	-u	Uninitialize. Clears initialization state.
  *	-w	Wait. Blocks until initializing has completed.
  */
 int
@@ -573,12 +574,14 @@ zpool_do_initialize(int argc, char **argv)
 	struct option long_options[] = {
 		{"cancel",	no_argument,		NULL, 'c'},
 		{"suspend",	no_argument,		NULL, 's'},
+		{"uninit",	no_argument,		NULL, 'u'},
 		{"wait",	no_argument,		NULL, 'w'},
 		{0, 0, 0, 0}
 	};
 
 	pool_initialize_func_t cmd_type = POOL_INITIALIZE_START;
-	while ((c = getopt_long(argc, argv, "csw", long_options, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "csuw", long_options,
+	    NULL)) != -1) {
 		switch (c) {
 		case 'c':
 			if (cmd_type != POOL_INITIALIZE_START &&
@@ -598,6 +601,15 @@ zpool_do_initialize(int argc, char **argv)
 			}
 			cmd_type = POOL_INITIALIZE_SUSPEND;
 			break;
+		case 'u':
+			if (cmd_type != POOL_INITIALIZE_START &&
+			    cmd_type != POOL_INITIALIZE_UNINIT) {
+				(void) fprintf(stderr, gettext("-u cannot be "
+				    "combined with other options\n"));
+				usage(B_FALSE);
+			}
+			cmd_type = POOL_INITIALIZE_UNINIT;
+			break;
 		case 'w':
 			wait = B_TRUE;
 			break;
@@ -624,8 +636,8 @@ zpool_do_initialize(int argc, char **argv)
 	}
 
 	if (wait && (cmd_type != POOL_INITIALIZE_START)) {
-		(void) fprintf(stderr, gettext("-w cannot be used with -c or "
-		    "-s\n"));
+		(void) fprintf(stderr, gettext("-w cannot be used with -c, -s"
+		    "or -u\n"));
 		usage(B_FALSE);
 	}
 
diff --git a/include/sys/fs/zfs.h b/include/sys/fs/zfs.h
index 2af11fc7196d..f69c3c231da7 100644
--- a/include/sys/fs/zfs.h
+++ b/include/sys/fs/zfs.h
@@ -1176,6 +1176,7 @@ typedef enum pool_initialize_func {
 	POOL_INITIALIZE_START,
 	POOL_INITIALIZE_CANCEL,
 	POOL_INITIALIZE_SUSPEND,
+	POOL_INITIALIZE_UNINIT,
 	POOL_INITIALIZE_FUNCS
 } pool_initialize_func_t;
 
@@ -1237,7 +1238,8 @@ typedef enum {
 	VDEV_INITIALIZE_ACTIVE,
 	VDEV_INITIALIZE_CANCELED,
 	VDEV_INITIALIZE_SUSPENDED,
-	VDEV_INITIALIZE_COMPLETE
+	VDEV_INITIALIZE_COMPLETE,
+	VDEV_INITIALIZE_UNINIT
 } vdev_initializing_state_t;
 
 typedef enum {
diff --git a/include/sys/vdev_initialize.h b/include/sys/vdev_initialize.h
index 81d39ebebcb2..942fc71c52ae 100644
--- a/include/sys/vdev_initialize.h
+++ b/include/sys/vdev_initialize.h
@@ -33,6 +33,7 @@ extern "C" {
 #endif
 
 extern void vdev_initialize(vdev_t *vd);
+extern void vdev_uninitialize(vdev_t *vd);
 extern void vdev_initialize_stop(vdev_t *vd,
     vdev_initializing_state_t tgt_state, list_t *vd_list);
 extern void vdev_initialize_stop_all(vdev_t *vd,
diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index a02fd198bed0..2c52021da3f1 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -7255,6 +7255,10 @@ spa_vdev_initialize_impl(spa_t *spa, uint64_t guid, uint64_t cmd_type,
 	    vd->vdev_initialize_state != VDEV_INITIALIZE_ACTIVE) {
 		mutex_exit(&vd->vdev_initialize_lock);
 		return (SET_ERROR(ESRCH));
+	} else if (cmd_type == POOL_INITIALIZE_UNINIT &&
+	    vd->vdev_initialize_thread != NULL) {
+		mutex_exit(&vd->vdev_initialize_lock);
+		return (SET_ERROR(EBUSY));
 	}
 
 	switch (cmd_type) {
@@ -7267,6 +7271,9 @@ spa_vdev_initialize_impl(spa_t *spa, uint64_t guid, uint64_t cmd_type,
 	case POOL_INITIALIZE_SUSPEND:
 		vdev_initialize_stop(vd, VDEV_INITIALIZE_SUSPENDED, vd_list);
 		break;
+	case POOL_INITIALIZE_UNINIT:
+		vdev_uninitialize(vd);
+		break;
 	default:
 		panic("invalid cmd_type %llu", (unsigned long long)cmd_type);
 	}
diff --git a/module/zfs/vdev_initialize.c b/module/zfs/vdev_initialize.c
index e9156c32f384..8bc20e1dacd9 100644
--- a/module/zfs/vdev_initialize.c
+++ b/module/zfs/vdev_initialize.c
@@ -81,7 +81,19 @@ vdev_initialize_zap_update_sync(void *arg, dmu_tx_t *tx)
 
 	objset_t *mos = vd->vdev_spa->spa_meta_objset;
 
-	if (last_offset > 0) {
+	uint64_t initialize_state = vd->vdev_initialize_state;
+
+	/*
+	 * XXX: need to double-check that there's really no way around this
+	 *
+	 * It turns out we call this with last_offset = 0 and
+	 * VDEV_INITIALIZE_NONE when resuming, so we can't just lob
+	 * VDEV_INITIALIZE_NONE out if we see it or we'll clobber that.
+	 */
+	if (last_offset > 0 || initialize_state == VDEV_INITIALIZE_UNINIT) {
+		if (initialize_state == VDEV_INITIALIZE_UNINIT) {
+			vd->vdev_initialize_state = VDEV_INITIALIZE_NONE;
+		}
 		vd->vdev_initialize_last_offset = last_offset;
 		VERIFY0(zap_update(mos, vd->vdev_leaf_zap,
 		    VDEV_LEAF_ZAP_INITIALIZE_LAST_OFFSET,
@@ -94,7 +106,7 @@ vdev_initialize_zap_update_sync(void *arg, dmu_tx_t *tx)
 		    1, &val, tx));
 	}
 
-	uint64_t initialize_state = vd->vdev_initialize_state;
+	initialize_state = vd->vdev_initialize_state;
 	VERIFY0(zap_update(mos, vd->vdev_leaf_zap,
 	    VDEV_LEAF_ZAP_INITIALIZE_STATE, sizeof (initialize_state), 1,
 	    &initialize_state, tx));
@@ -149,6 +161,10 @@ vdev_initialize_change_state(vdev_t *vd, vdev_initializing_state_t new_state)
 		spa_history_log_internal(spa, "initialize", tx,
 		    "vdev=%s complete", vd->vdev_path);
 		break;
+	case VDEV_INITIALIZE_UNINIT:
+		spa_history_log_internal(spa, "uninitialize", tx,
+		    "vdev=%s", vd->vdev_path);
+		break;
 	default:
 		panic("invalid state %llu", (unsigned long long)new_state);
 	}
@@ -603,6 +619,24 @@ vdev_initialize(vdev_t *vd)
 	    vdev_initialize_thread, vd, 0, &p0, TS_RUN, maxclsyspri);
 }
 
+/*
+ * Uninitializes a device. Caller must hold vdev_initialize_lock.
+ * Device must be a leaf and not already be initializing.
+ */
+void
+vdev_uninitialize(vdev_t *vd)
+{
+	ASSERT(MUTEX_HELD(&vd->vdev_initialize_lock));
+	ASSERT(vd->vdev_ops->vdev_op_leaf);
+	ASSERT(vdev_is_concrete(vd));
+	ASSERT3P(vd->vdev_initialize_thread, ==, NULL);
+	ASSERT(!vd->vdev_detached);
+	ASSERT(!vd->vdev_initialize_exit_wanted);
+	ASSERT(!vd->vdev_top->vdev_removing);
+
+	vdev_initialize_change_state(vd, VDEV_INITIALIZE_UNINIT);
+}
+
 /*
  * Wait for the initialize thread to be terminated (cancelled or stopped).
  */
@@ -758,6 +792,7 @@ vdev_initialize_restart(vdev_t *vd)
 }
 
 EXPORT_SYMBOL(vdev_initialize);
+EXPORT_SYMBOL(vdev_uninitialize);
 EXPORT_SYMBOL(vdev_initialize_stop);
 EXPORT_SYMBOL(vdev_initialize_stop_all);
 EXPORT_SYMBOL(vdev_initialize_stop_wait);
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index 96a021acbc95..ec8637cd9a18 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -3981,7 +3981,8 @@ zfs_ioc_pool_initialize(const char *poolname, nvlist_t *innvl, nvlist_t *outnvl)
 
 	if (!(cmd_type == POOL_INITIALIZE_CANCEL ||
 	    cmd_type == POOL_INITIALIZE_START ||
-	    cmd_type == POOL_INITIALIZE_SUSPEND)) {
+	    cmd_type == POOL_INITIALIZE_SUSPEND ||
+	    cmd_type == POOL_INITIALIZE_UNINIT)) {
 		return (SET_ERROR(EINVAL));
 	}