diff --git a/usr.bin/procstat/Makefile b/usr.bin/procstat/Makefile
--- a/usr.bin/procstat/Makefile
+++ b/usr.bin/procstat/Makefile
@@ -5,6 +5,7 @@
 PROG=	procstat
 MAN=	procstat.1
 SRCS=	procstat.c		\
+	procstat_advlock.c	\
 	procstat_args.c		\
 	procstat_auxv.c		\
 	procstat_basic.c	\
diff --git a/usr.bin/procstat/procstat.h b/usr.bin/procstat/procstat.h
--- a/usr.bin/procstat/procstat.h
+++ b/usr.bin/procstat/procstat.h
@@ -44,6 +44,7 @@
 	PS_OPT_SIGNUM		= 0x08,
 	PS_OPT_VERBOSE		= 0x10,
 	PS_MODE_COMPAT		= 0x20,
+	PS_MODE_NO_KINFO_PROC	= 0x40,
 };
 
 #define PS_SUBCOMMAND_OPTS			\
@@ -56,6 +57,7 @@
 void	kinfo_proc_sort(struct kinfo_proc *kipp, int count);
 const char *	kinfo_proc_thread_name(const struct kinfo_proc *kipp);
 
+void	procstat_advlocks(struct procstat *prstat, struct kinfo_proc *kipp);
 void	procstat_args(struct procstat *prstat, struct kinfo_proc *kipp);
 void	procstat_auxv(struct procstat *prstat, struct kinfo_proc *kipp);
 void	procstat_basic(struct procstat *prstat, struct kinfo_proc *kipp);
diff --git a/usr.bin/procstat/procstat.1 b/usr.bin/procstat/procstat.1
--- a/usr.bin/procstat/procstat.1
+++ b/usr.bin/procstat/procstat.1
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd February 13, 2021
+.Dd April 7, 2022
 .Dt PROCSTAT 1
 .Os
 .Sh NAME
@@ -144,6 +144,22 @@
 The following commands are available for
 .Nm :
 .Bl -tag -width indent
+.It Ar advlock
+Print information about advisory locks on files.
+All three types of locks are listed, BSD-style
+.Xr lockf 2 ,
+POSIX-style
+.Xr fcntl 2
+.Va F_SETLK ,
+and remote
+.Xr lockd 8
+locks used by NFSv3.
+Note that neither the
+.Fl a
+option nor
+.Va pid
+list can be used to limit the display of the locks, mostly because
+some types of locks do not have local (or any) owning processes.
 .It Ar basic
 Print basic process statistics (this is the default).
 .It Ar binary | Fl b
diff --git a/usr.bin/procstat/procstat.c b/usr.bin/procstat/procstat.c
--- a/usr.bin/procstat/procstat.c
+++ b/usr.bin/procstat/procstat.c
@@ -87,6 +87,8 @@
 
 /* procstat parameters and arguments */
 static const struct procstat_cmd cmd_table[] = {
+	{ "advlock", "advisory_locks", NULL, &procstat_advlocks, &cmdopt_none,
+	    PS_CMP_PLURAL | PS_CMP_SUBSTR | PS_MODE_NO_KINFO_PROC },
 	{ "argument", "arguments", NULL, &procstat_args, &cmdopt_none,
 	    PS_CMP_PLURAL | PS_CMP_SUBSTR },
 	{ "auxv", "auxv", NULL, &procstat_auxv, &cmdopt_none, PS_CMP_NORMAL },
@@ -449,7 +451,8 @@
 	}
 
 	/* Must specify either the -a flag or a list of pids. */
-	if (!(aflag == 1 && argc == 0) && !(aflag == 0 && argc > 0))
+	if (!(aflag == 1 && argc == 0) && !(aflag == 0 && argc > 0) &&
+	    (cmd->cmp & PS_MODE_NO_KINFO_PROC) == 0)
 		usage(cmd);
 
 	if (memf != NULL)
@@ -465,6 +468,11 @@
 		xo_open_container(progname);
 		xo_open_container(xocontainer);
 
+		if ((cmd->cmp & PS_MODE_NO_KINFO_PROC) != 0) {
+			cmd->cmd(prstat, NULL);
+			goto iter;
+		}
+
 		if (aflag) {
 			p = procstat_getprocs(prstat, KERN_PROC_PROC, 0, &cnt);
 			if (p == NULL)
@@ -520,6 +528,7 @@
 			}
 		}
 
+iter:
 		xo_close_container(xocontainer);
 		xo_close_container(progname);
 		xo_finish();
diff --git a/usr.bin/procstat/procstat_advlock.c b/usr.bin/procstat/procstat_advlock.c
new file mode 100644
--- /dev/null
+++ b/usr.bin/procstat/procstat_advlock.c
@@ -0,0 +1,102 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2022 The FreeBSD Foundation
+ *
+ * Portions of this software were developed by Konstantin Belousov
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <sys/user.h>
+
+#include <err.h>
+#include <libprocstat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "procstat.h"
+
+void
+procstat_advlocks(struct procstat *prstat, struct kinfo_proc *kipp __unused)
+{
+	struct advlock_list *advl;
+	struct advlock *a;
+	static const char advisory_lock_item[] = "advisory_lock";
+
+	if ((procstat_opts & PS_OPT_NOHEADER) == 0)
+		xo_emit("{T:/%-3s %-5s %-5s %-6s %-18s %-18s "
+		    "%-8s %-9s %-9s %-12s}\n", "RW", "TYPE", "PID", "SYSID",
+		    "FSID", "RDEV", "INO", "START", "LEN", "PATH");
+
+	xo_open_list(advisory_lock_item);
+	advl = procstat_getadvlock(prstat);
+	if (advl == NULL) {
+		xo_close_list(advisory_lock_item);
+		return;
+	}
+
+	STAILQ_FOREACH(a, advl, next) {
+		xo_open_instance(advisory_lock_item);
+		switch (a->rw) {
+		case PS_ADVLOCK_RO:
+			xo_emit("{:rw/%s} ", "RO");
+			break;
+		case PS_ADVLOCK_RW:
+			xo_emit("{:rw/%s} ", "RW");
+			break;
+		default:
+			xo_emit("{:rw/%s} ", "??");
+			break;
+		}
+		switch (a->type) {
+		case PS_ADVLOCK_TYPE_FLOCK:
+			xo_emit("{:type/%s} ", "FLOCK");
+			break;
+		case PS_ADVLOCK_TYPE_PID:
+			xo_emit("{:type/%s} ", "FCNTL");
+			break;
+		case PS_ADVLOCK_TYPE_REMOTE:
+			xo_emit("{:type/%s} ", "LOCKD");
+			break;
+		default:
+			xo_emit("{:type/%s} ", "?????");
+			break;
+		}
+		xo_emit("{:pid/%5d} ", a->pid);
+		xo_emit("{:sysid/%5d} ", a->sysid);
+		xo_emit("{:fsid/%18#jx} ", (uintmax_t)a->file_fsid);
+		xo_emit("{:rdev/%#18jx} ", (uintmax_t)a->file_rdev);
+		xo_emit("{:ino/%8ju} ", (uintmax_t)a->file_fileid);
+		xo_emit("{:start/%9ju} ", (uintmax_t)a->start);
+		xo_emit("{:len/%9ju} ", (uintmax_t)a->len);
+		xo_emit("{:path/%s}", a->path == NULL ? "" : a->path);
+		xo_emit("\n");
+		xo_close_instance(advisory_lock_item);
+	}
+	xo_close_list(advisory_lock_item);
+	procstat_freeadvlock(prstat, advl);
+}