diff --git a/usr.bin/truss/syscall.h b/usr.bin/truss/syscall.h
index be5da1ece4f..e3737ccbfa1 100644
--- a/usr.bin/truss/syscall.h
+++ b/usr.bin/truss/syscall.h
@@ -50,7 +50,7 @@ enum Argtype { None = 1, Hex, Octal, Int, UInt, LongHex, Name, Ptr, Stat, Ioctl,
 	Kldunloadflags, Sizet, Madvice, Socklent, Sockprotocol, Sockoptlevel,
 	Sockoptname, Msgflags, CapRights, PUInt, PQuadHex, Acltype,
 	Extattrnamespace, Minherit, Mlockall, Mountflags, Msync, Priowhich,
-	Ptraceop,
+	Ptraceop, Quotactlcmd,
 
 	CloudABIAdvice, CloudABIClockID, ClouduABIFDSFlags,
 	CloudABIFDStat, CloudABIFileStat, CloudABIFileType,
diff --git a/usr.bin/truss/syscalls.c b/usr.bin/truss/syscalls.c
index 6df97c28953..9373f70625c 100644
--- a/usr.bin/truss/syscalls.c
+++ b/usr.bin/truss/syscalls.c
@@ -366,6 +366,8 @@ static struct syscall decoded_syscalls[] = {
 	{ .name = "pwrite", .ret_type = 1, .nargs = 4,
 	  .args = { { Int, 0 }, { BinString | IN, 1 }, { Sizet, 2 },
 		    { QuadHex, 3 } } },
+	{ .name = "quotactl", .ret_type = 1, .nargs = 4,
+	  .args = { { Name, 0 }, { Quotactlcmd, 1 }, { Int, 2 }, { Ptr, 3 } } },
 	{ .name = "read", .ret_type = 1, .nargs = 3,
 	  .args = { { Int, 0 }, { BinString | OUT, 1 }, { Sizet, 2 } } },
 	{ .name = "readlink", .ret_type = 1, .nargs = 3,
@@ -2136,6 +2138,10 @@ print_arg(struct syscall_args *sc, unsigned long *args, long *retval,
 		print_integer_arg(sysdecode_ptrace_request, fp,
 		    args[sc->offset]);
 		break;
+	case Quotactlcmd:
+		if (!sysdecode_quotactl_cmd(fp, args[sc->offset]))
+			fprintf(fp, "%#x", (int)args[sc->offset]);
+		break;
 
 	case CloudABIAdvice:
 		fputs(xlookup(cloudabi_advice, args[sc->offset]), fp);