diff --git a/include/labwc.h b/include/labwc.h
index 834b1b9a..9abe32b2 100644
--- a/include/labwc.h
+++ b/include/labwc.h
@@ -47,6 +47,7 @@
 #include "config/keybind.h"
 #include "config/rcxml.h"
 #include "regions.h"
+#include "session-lock.h"
 #if HAVE_NLS
 #include <libintl.h>
 #include <locale.h>
@@ -283,6 +284,8 @@ struct server {
 	 */
 	int pending_output_layout_change;
 
+	struct session_lock *session_lock;
+
 	struct wlr_foreign_toplevel_manager_v1 *foreign_toplevel_manager;
 
 	struct wlr_drm_lease_v1_manager *drm_lease_manager;
@@ -319,6 +322,7 @@ struct output {
 	struct wlr_scene_tree *layer_tree[LAB_NR_LAYERS];
 	struct wlr_scene_tree *layer_popup_tree;
 	struct wlr_scene_tree *osd_tree;
+	struct wlr_scene_tree *session_lock_tree;
 	struct wlr_scene_buffer *workspace_osd;
 	struct wlr_box usable_area;
 
diff --git a/include/session-lock.h b/include/session-lock.h
new file mode 100644
index 00000000..aea4e4bd
--- /dev/null
+++ b/include/session-lock.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __LAB_SESSION_LOCK_H
+#define __LAB_SESSION_LOCK_H
+
+#include <wlr/types/wlr_session_lock_v1.h>
+
+struct session_lock {
+	struct wlr_session_lock_v1 *lock;
+	struct wlr_surface *focused;
+	bool abandoned;
+
+	struct wl_list session_lock_outputs;
+
+	struct wl_listener new_surface;
+	struct wl_listener unlock;
+	struct wl_listener destroy;
+};
+
+void session_lock_init(struct server *server);
+void session_lock_output_create(struct session_lock *lock, struct output *output);
+
+#endif /* __LAB_SESSION_LOCK_H */
diff --git a/src/desktop.c b/src/desktop.c
index 91c15ce8..5a4acffa 100644
--- a/src/desktop.c
+++ b/src/desktop.c
@@ -50,7 +50,8 @@ desktop_focus_and_activate_view(struct seat *seat, struct view *view)
 		return;
 	}
 
-	if (input_inhibit_blocks_surface(seat, view->surface->resource)) {
+	if (input_inhibit_blocks_surface(seat, view->surface->resource)
+			|| seat->server->session_lock) {
 		return;
 	}
 
diff --git a/src/keyboard.c b/src/keyboard.c
index f48b6dbc..3f69c8bc 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -145,6 +145,9 @@ handle_compositor_keybindings(struct keyboard *keyboard,
 	if (seat->active_client_while_inhibited) {
 		return false;
 	}
+	if (seat->server->session_lock) {
+		return false;
+	}
 
 	/*
 	 * If a user lets go of the modifier (e.g. alt) before the 'normal' key
diff --git a/src/meson.build b/src/meson.build
index a3f521bd..5087d331 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -18,6 +18,7 @@ labwc_sources = files(
   'resistance.c',
   'seat.c',
   'server.c',
+  'session-lock.c',
   'touch.c',
   'theme.c',
   'view.c',
diff --git a/src/output.c b/src/output.c
index 1183add4..f5af8ab4 100644
--- a/src/output.c
+++ b/src/output.c
@@ -54,6 +54,7 @@ output_destroy_notify(struct wl_listener *listener, void *data)
 	}
 	wlr_scene_node_destroy(&output->layer_popup_tree->node);
 	wlr_scene_node_destroy(&output->osd_tree->node);
+	wlr_scene_node_destroy(&output->session_lock_tree->node);
 
 	struct view *view;
 	struct server *server = output->server;
@@ -183,6 +184,9 @@ new_output_notify(struct wl_listener *listener, void *data)
 	output->osd_tree = wlr_scene_tree_create(&server->scene->tree);
 	node_descriptor_create(&output->osd_tree->node,
 		LAB_NODE_DESC_TREE, NULL);
+	output->session_lock_tree = wlr_scene_tree_create(&server->scene->tree);
+	node_descriptor_create(&output->session_lock_tree->node,
+		LAB_NODE_DESC_TREE, NULL);
 
 	/*
 	 * Set the z-positions to achieve the following order (from top to
@@ -228,6 +232,10 @@ new_output_notify(struct wl_listener *listener, void *data)
 	/* Create regions from config */
 	regions_reconfigure_output(output);
 
+	if (server->session_lock) {
+		session_lock_output_create(server->session_lock, output);
+	}
+
 	server->pending_output_layout_change--;
 	do_output_layout_change(server);
 }
diff --git a/src/server.c b/src/server.c
index 24aa1cb3..efc4e2f2 100644
--- a/src/server.c
+++ b/src/server.c
@@ -387,6 +387,8 @@ server_init(struct server *server)
 	server->foreign_toplevel_manager =
 		wlr_foreign_toplevel_manager_v1_create(server->wl_display);
 
+	session_lock_init(server);
+
 	server->drm_lease_manager = wlr_drm_lease_v1_manager_create(
 		server->wl_display, server->backend);
 	if (server->drm_lease_manager) {
diff --git a/src/session-lock.c b/src/session-lock.c
new file mode 100644
index 00000000..4e09e1ee
--- /dev/null
+++ b/src/session-lock.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#define _POSIX_C_SOURCE 200809L
+#include <assert.h>
+#include "common/mem.h"
+#include "labwc.h"
+
+static struct wl_listener new_lock;
+static struct wl_listener manager_destroy;
+static struct wlr_session_lock_manager_v1 *wlr_session_lock_manager;
+
+static struct server *g_server;
+
+struct session_lock_output {
+	struct wlr_scene_tree *tree;
+	struct wlr_scene_rect *background;
+	struct session_lock *lock;
+	struct output *output;
+	struct wlr_session_lock_surface_v1 *surface;
+
+	struct wl_list link; /* session_lock.outputs */
+
+	struct wl_listener destroy;
+	struct wl_listener commit;
+	struct wl_listener surface_destroy;
+	struct wl_listener surface_map;
+};
+
+static void
+focus_surface(struct session_lock *lock, struct wlr_surface *focused)
+{
+	lock->focused = focused;
+	seat_focus_surface(&g_server->seat, focused);
+}
+
+static void
+refocus_output(struct session_lock_output *output)
+{
+	/* Try to focus another session-lock surface */
+	if (output->lock->focused != output->surface->surface) {
+		return;
+	}
+
+	struct session_lock_output *iter;
+	wl_list_for_each(iter, &output->lock->session_lock_outputs, link) {
+		if (iter == output || !iter->surface) {
+			continue;
+		}
+		if (iter->surface->mapped) {
+			focus_surface(output->lock, iter->surface->surface);
+			return;
+		}
+	}
+	focus_surface(output->lock, NULL);
+}
+
+static void
+handle_surface_map(struct wl_listener *listener, void *data)
+{
+	struct session_lock_output *surf = wl_container_of(listener, surf, surface_map);
+	if (!surf->lock->focused) {
+		focus_surface(surf->lock, surf->surface->surface);
+	}
+}
+
+static void
+handle_surface_destroy(struct wl_listener *listener, void *data)
+{
+	struct session_lock_output *output =
+		wl_container_of(listener, output, surface_destroy);
+	refocus_output(output);
+
+	assert(output->surface);
+	output->surface = NULL;
+	wl_list_remove(&output->surface_destroy.link);
+	wl_list_remove(&output->surface_map.link);
+}
+
+static void
+lock_output_reconfigure(struct session_lock_output *output)
+{
+	struct wlr_box box;
+	wlr_output_layout_get_box(g_server->output_layout, output->output->wlr_output, &box);
+	wlr_scene_rect_set_size(output->background, box.width, box.height);
+	if (output->surface) {
+		wlr_session_lock_surface_v1_configure(output->surface, box.width, box.height);
+	}
+}
+
+static void
+handle_new_surface(struct wl_listener *listener, void *data)
+{
+	struct session_lock *lock = wl_container_of(listener, lock, new_surface);
+	struct wlr_session_lock_surface_v1 *lock_surface = data;
+	struct output *output = lock_surface->output->data;
+	struct session_lock_output *lock_output;
+	wl_list_for_each(lock_output, &lock->session_lock_outputs, link) {
+		if (lock_output->output == output) {
+			goto found_lock_output;
+		}
+	}
+	wlr_log(WLR_ERROR, "new lock surface, but no output");
+	/* TODO: Consider improving security by handling this better */
+	return;
+
+found_lock_output:
+	lock_output->surface = lock_surface;
+	wlr_scene_subsurface_tree_create(lock_output->tree, lock_surface->surface);
+
+	lock_output->surface_destroy.notify = handle_surface_destroy;
+	wl_signal_add(&lock_surface->events.destroy, &lock_output->surface_destroy);
+
+	lock_output->surface_map.notify = handle_surface_map;
+	wl_signal_add(&lock_surface->events.map, &lock_output->surface_map);
+
+	lock_output_reconfigure(lock_output);
+}
+
+static void
+session_lock_output_destroy(struct session_lock_output *output)
+{
+	if (output->surface) {
+		refocus_output(output);
+		wl_list_remove(&output->surface_destroy.link);
+		wl_list_remove(&output->surface_map.link);
+	}
+	wl_list_remove(&output->commit.link);
+	wl_list_remove(&output->destroy.link);
+	wl_list_remove(&output->link);
+	free(output);
+}
+
+static void
+handle_destroy(struct wl_listener *listener, void *data)
+{
+	struct session_lock_output *output = wl_container_of(listener, output, destroy);
+	session_lock_output_destroy(output);
+}
+
+static void
+handle_commit(struct wl_listener *listener, void *data)
+{
+	struct wlr_output_event_commit *event = data;
+	struct session_lock_output *output = wl_container_of(listener, output, commit);
+	uint32_t require_reconfigure = WLR_OUTPUT_STATE_MODE
+		| WLR_OUTPUT_STATE_SCALE | WLR_OUTPUT_STATE_TRANSFORM;
+	if (event->committed & require_reconfigure) {
+		lock_output_reconfigure(output);
+	}
+}
+
+void
+session_lock_output_create(struct session_lock *lock, struct output *output)
+{
+	struct session_lock_output *lock_output = znew(*lock_output);
+	if (!lock_output) {
+		wlr_log(WLR_ERROR, "session-lock: out of memory");
+		goto exit_session;
+	}
+
+	struct wlr_scene_tree *tree = wlr_scene_tree_create(output->session_lock_tree);
+	if (!tree) {
+		wlr_log(WLR_ERROR, "session-lock: wlr_scene_tree_create()");
+		free(lock_output);
+		goto exit_session;
+	}
+
+	/*
+	 * The ext-session-lock protocol says that the compositor should blank
+	 * all outputs with an opaque color such that their normal content is
+	 * fully hidden
+	 */
+	float *black = (float[4]) { 0.f, 0.f, 0.f, 1.f };
+	struct wlr_scene_rect *background = wlr_scene_rect_create(tree, 0, 0, black);
+	if (!background) {
+		wlr_log(WLR_ERROR, "session-lock: wlr_scene_rect_create()");
+		wlr_scene_node_destroy(&tree->node);
+		free(lock_output);
+		goto exit_session;
+	}
+
+	struct wlr_box box;
+	wlr_output_layout_get_box(g_server->output_layout, output->wlr_output, &box);
+	wlr_scene_node_set_position(&output->session_lock_tree->node, box.x, box.y);
+
+	lock_output->output = output;
+	lock_output->tree = tree;
+	lock_output->background = background;
+	lock_output->lock = lock;
+
+	lock_output->destroy.notify = handle_destroy;
+	wl_signal_add(&tree->node.events.destroy, &lock_output->destroy);
+
+	lock_output->commit.notify = handle_commit;
+	wl_signal_add(&output->wlr_output->events.commit, &lock_output->commit);
+
+	lock_output_reconfigure(lock_output);
+
+	wl_list_insert(&lock->session_lock_outputs, &lock_output->link);
+	return;
+
+exit_session:
+	/* TODO: Consider a better - but secure - way to deal with this */
+	wlr_log(WLR_ERROR, "out of memory");
+	exit(EXIT_FAILURE);
+}
+
+static void
+session_lock_destroy(struct session_lock *lock)
+{
+	struct session_lock_output *lock_output, *next;
+	wl_list_for_each_safe(lock_output, next, &lock->session_lock_outputs, link) {
+		wlr_scene_node_destroy(&lock_output->tree->node);
+	}
+	if (g_server->session_lock == lock) {
+		g_server->session_lock = NULL;
+	}
+	if (!lock->abandoned) {
+		wl_list_remove(&lock->destroy.link);
+		wl_list_remove(&lock->unlock.link);
+		wl_list_remove(&lock->new_surface.link);
+	}
+	free(lock);
+}
+
+static void
+handle_unlock(struct wl_listener *listener, void *data)
+{
+	struct session_lock *lock = wl_container_of(listener, lock, unlock);
+	session_lock_destroy(lock);
+	desktop_focus_topmost_mapped_view(g_server);
+}
+
+static void
+handle_session_lock_destroy(struct wl_listener *listener, void *data)
+{
+	struct session_lock *lock = wl_container_of(listener, lock, destroy);
+
+	float *black = (float[4]) { 0.f, 0.f, 0.f, 1.f };
+	struct session_lock_output *lock_output;
+	wl_list_for_each(lock_output, &lock->session_lock_outputs, link) {
+		wlr_scene_rect_set_color(lock_output->background, black);
+	}
+
+	lock->abandoned = true;
+	wl_list_remove(&lock->destroy.link);
+	wl_list_remove(&lock->unlock.link);
+	wl_list_remove(&lock->new_surface.link);
+}
+
+static void
+handle_new_session_lock(struct wl_listener *listener, void *data)
+{
+	struct wlr_session_lock_v1 *lock = data;
+
+	/* One already exists */
+	if (g_server->session_lock) {
+		if (g_server->session_lock->abandoned) {
+			wlr_log(WLR_INFO, "replacing abandoned lock");
+			session_lock_destroy(g_server->session_lock);
+		} else {
+			wlr_log(WLR_ERROR, "session already locked");
+			wlr_session_lock_v1_destroy(lock);
+			return;
+		}
+	}
+
+	struct session_lock *session_lock = znew(*session_lock);
+	if (!session_lock) {
+		wlr_log(WLR_ERROR, "session-lock: out of memory");
+		wlr_session_lock_v1_destroy(lock);
+		return;
+	}
+
+	wl_list_init(&session_lock->session_lock_outputs);
+	struct output *output;
+	wl_list_for_each(output, &g_server->outputs, link) {
+		session_lock_output_create(session_lock, output);
+	}
+
+	session_lock->new_surface.notify = handle_new_surface;
+	wl_signal_add(&lock->events.new_surface, &session_lock->new_surface);
+
+	session_lock->unlock.notify = handle_unlock;
+	wl_signal_add(&lock->events.unlock, &session_lock->unlock);
+
+	session_lock->destroy.notify = handle_session_lock_destroy;
+	wl_signal_add(&lock->events.destroy, &session_lock->destroy);
+
+	wlr_session_lock_v1_send_locked(lock);
+	g_server->session_lock = session_lock;
+}
+
+static void
+handle_manager_destroy(struct wl_listener *listener, void *data)
+{
+	if (g_server->session_lock) {
+		session_lock_destroy(g_server->session_lock);
+	}
+	wl_list_remove(&new_lock.link);
+	wl_list_remove(&manager_destroy.link);
+	wlr_session_lock_manager = NULL;
+}
+
+void session_lock_init(struct server *server)
+{
+	g_server = server;
+	wlr_session_lock_manager = wlr_session_lock_manager_v1_create(server->wl_display);
+
+	new_lock.notify = handle_new_session_lock;
+	wl_signal_add(&wlr_session_lock_manager->events.new_lock, &new_lock);
+
+	manager_destroy.notify = handle_manager_destroy;
+	wl_signal_add(&wlr_session_lock_manager->events.destroy, &manager_destroy);
+}