diff --git a/usr.bin/fstat/fuser.1 b/usr.bin/fstat/fuser.1
--- a/usr.bin/fstat/fuser.1
+++ b/usr.bin/fstat/fuser.1
@@ -22,7 +22,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd June 18, 2020
+.Dd June 3, 2025
 .Dt FUSER 1
 .Os
 .Sh NAME
@@ -30,6 +30,7 @@
 .Nd list IDs of all processes that have one or more files open
 .Sh SYNOPSIS
 .Nm
+.Op Fl -libxo
 .Op Fl cfkmu
 .Op Fl M Ar core
 .Op Fl N Ar system
@@ -54,6 +55,13 @@
 .Pp
 The following options are available:
 .Bl -tag -width indent
+.It Fl -libxo
+Generate output via
+.Xr libxo 3
+in a selection of different human and machine readable formats.
+See
+.Xr xo_parse_args 3
+for details on command line arguments.
 .It Fl c
 Treat files as mount points and report on any files open in the file system.
 .It Fl f
@@ -120,6 +128,8 @@
 .Xr fstat 1 ,
 .Xr ps 1 ,
 .Xr systat 1 ,
+.Xr libxo 3 ,
+.Xr xo_parse_args 3 ,
 .Xr iostat 8 ,
 .Xr pstat 8 ,
 .Xr vmstat 8
diff --git a/usr.bin/fstat/fuser.c b/usr.bin/fstat/fuser.c
--- a/usr.bin/fstat/fuser.c
+++ b/usr.bin/fstat/fuser.c
@@ -37,6 +37,7 @@
 #include <err.h>
 #include <fcntl.h>
 #include <libprocstat.h>
+#include <libxo/xo.h>
 #include <limits.h>
 #include <paths.h>
 #include <pwd.h>
@@ -115,8 +116,7 @@
 static void
 usage(void)
 {
-
-	fprintf(stderr,
+	xo_error(
 "usage: fuser [-cfhkmu] [-M core] [-N system] [-s signal] file ...\n");
 	exit(EX_USAGE);
 }
@@ -129,10 +129,10 @@
 	assert(cons);
 	for (i = 0; i < NUFLAGS; i++)
 		if ((cons->uflags & uflags[i].flag) != 0)
-			fputc(uflags[i].ch, stderr);
+			xo_emit_err("{:uflag/%c}", uflags[i].ch);
 	for (i = 0; i < NFFLAGS; i++)
 		if ((cons->flags & fflags[i].flag) != 0)
-			fputc(fflags[i].ch, stderr);
+			xo_emit_err("{:fflag/%c}", fflags[i].ch);
 }
 
 /*
@@ -145,7 +145,7 @@
 
 	assert(path);
 	if (stat(path, &sb) != 0) {
-		warn("%s", path);
+		xo_warn("%s", path);
 		return (1);
 	}
 	reqfile->fileid = sb.st_ino;
@@ -166,6 +166,10 @@
 	int ch, sig;
 	unsigned int i, cnt, nfiles;
 
+	argc = xo_parse_args(argc, argv);
+	if (argc < 0)
+		exit(EX_USAGE);
+
 	sig = SIGKILL;	/* Default to kill. */
 	nlistf = NULL;
 	memf = NULL;
@@ -198,7 +202,7 @@
 			break;
 		case 's':
 			if (str2sig(optarg, &sig) != 0)
-				errx(EX_USAGE, "invalid signal: %s", optarg);
+				xo_errx(EX_USAGE, "invalid signal: %s", optarg);
 			break;
 		case 'h':
 			/* PASSTHROUGH */
@@ -219,23 +223,23 @@
 	 */
 	reqfiles = malloc(argc * sizeof(struct reqfile));
 	if (reqfiles == NULL)
-		err(EX_OSERR, "malloc()");
+		xo_err(EX_OSERR, "malloc()");
 	nfiles = 0;
 	while (argc--)
 		if (!addfile(*(argv++), &reqfiles[nfiles]))
 			nfiles++;
 	if (nfiles == 0)
-		errx(EX_IOERR, "files not accessible");
+		xo_errx(EX_IOERR, "files not accessible");
 
 	if (memf != NULL)
 		procstat = procstat_open_kvm(nlistf, memf);
 	else
 		procstat = procstat_open_sysctl();
 	if (procstat == NULL)
-		errx(1, "procstat_open()");
+		xo_errx(1, "procstat_open()");
 	procs = procstat_getprocs(procstat, KERN_PROC_PROC, 0, &cnt);
 	if (procs == NULL)
-		 errx(1, "procstat_getprocs()");
+		xo_errx(1, "procstat_getprocs()");
 
 	/*
 	 * Walk through process table and look for matching files.
@@ -244,27 +248,34 @@
 		if (procs[i].ki_stat != SZOMB)
 			dofiles(procstat, &procs[i], reqfiles, nfiles);
 
+	xo_open_container("files");
 	for (i = 0; i < nfiles; i++) {
-		fprintf(stderr, "%s:", reqfiles[i].name);
+		xo_error("%s:", reqfiles[i].name);
 		fflush(stderr);
-		STAILQ_FOREACH(consumer, &reqfiles[i].consumers, next) {
-			if (consumer->flags != 0) {
-				fprintf(stdout, "%6d", consumer->pid);
-				fflush(stdout);
-				printflags(consumer);
-				if ((flags & UFLAG) != 0)
-					fprintf(stderr, "(%s)",
-					    user_from_uid(consumer->uid, 0));
-				if ((flags & KFLAG) != 0)
-					kill(consumer->pid, sig);
-				fflush(stderr);
+		xo_open_list("consumers");
+			STAILQ_FOREACH(consumer, &reqfiles[i].consumers, next) {
+				if (consumer->flags != 0) {
+					xo_open_instance("consumer");
+					xo_emit("{:pid/%6d/%d}", consumer->pid);
+					xo_flush();
+					printflags(consumer);
+					if ((flags & UFLAG) != 0)
+						xo_error("(%s)",
+							user_from_uid(consumer->uid, 0));
+					if ((flags & KFLAG) != 0)
+						kill(consumer->pid, sig);
+					fflush(stderr);
+					xo_close_instance("consumer");
+				}
 			}
-		}
-		(void)fprintf(stderr, "\n");
+		xo_close_list("consumers");
+		xo_emit("{D:/\n}");
 	}
+	xo_close_container("files");
 	procstat_freeprocs(procstat, procs);
 	procstat_close(procstat);
 	free(reqfiles);
+	xo_finish();
 	return (0);
 }
 
@@ -325,7 +336,7 @@
 			 */
 			cons = calloc(1, sizeof(struct consumer));
 			if (cons == NULL) {
-				warn("malloc()");
+				xo_warn("malloc()");
 				continue;
 			}
 			cons->uid = kp->ki_uid;