diff --git a/doc/user-guide b/doc/user-guide
index 1121ba26..cb3eb11c 100644
--- a/doc/user-guide
+++ b/doc/user-guide
@@ -203,6 +203,7 @@ Sortix comes with a number of home-made programs. Here is an overview:
 * `mv` - move a file
 * `pager` - display file page by page
 * `ps` - report a snapshot of the current processes
+* `pstree` - display a tree of processes
 * `pwd` - print current directory path
 * `realpath` - canonicalize filesystem paths
 * `regress` - run system tests
diff --git a/utils/.gitignore b/utils/.gitignore
index 5041ce50..90306a79 100644
--- a/utils/.gitignore
+++ b/utils/.gitignore
@@ -30,6 +30,7 @@ mktemp
 mv
 pager
 ps
+pstree
 pwd
 realpath
 rm
diff --git a/utils/Makefile b/utils/Makefile
index e943f23b..f9007d81 100644
--- a/utils/Makefile
+++ b/utils/Makefile
@@ -42,6 +42,7 @@ mktemp \
 mv \
 pager \
 ps \
+pstree \
 pwd \
 realpath \
 rm \
diff --git a/utils/pstree.cpp b/utils/pstree.cpp
new file mode 100644
index 00000000..1fd3a12a
--- /dev/null
+++ b/utils/pstree.cpp
@@ -0,0 +1,197 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2015.
+
+    This program is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    This program is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+    more details.
+
+    You should have received a copy of the GNU General Public License along with
+    this program. If not, see <http://www.gnu.org/licenses/>.
+
+    pstree.cpp
+    Lists processes in a nice tree.
+
+*******************************************************************************/
+
+#include <sys/types.h>
+
+#include <err.h>
+#include <errno.h>
+#include <locale.h>
+#include <psctl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+const char* last_basename(const char* path)
+{
+	const char* result = path;
+	for ( size_t i = 0; path[i]; i++ )
+		if ( path[i] == '/' && path[i + 1] != '/' && path[i + 1] )
+			result = path + i + 1;
+	return result;
+}
+
+static char* get_program_path_of_pid(pid_t pid)
+{
+	struct psctl_program_path ctl;
+	memset(&ctl, 0, sizeof(ctl));
+	ctl.buffer = NULL;
+	ctl.size = 0;
+	if ( psctl(pid, PSCTL_PROGRAM_PATH, &ctl) < 0 )
+		return NULL;
+	while ( true )
+	{
+		char* new_buffer = (char*) realloc(ctl.buffer, ctl.size);
+		if ( !new_buffer )
+			return free(ctl.buffer), (char*) NULL;
+		ctl.buffer = new_buffer;
+		if ( psctl(pid, PSCTL_PROGRAM_PATH, &ctl) == 0 )
+			return ctl.buffer;
+		if ( errno != ERANGE )
+			return free(ctl.buffer), (char*) NULL;
+	}
+}
+
+static void pstree(pid_t pid, const char* prefix, bool continuation)
+{
+	while ( pid != -1 )
+	{
+		struct psctl_stat psst;
+		if ( psctl(pid, PSCTL_STAT, &psst) < 0 )
+		{
+			if ( errno != ESRCH )
+				warn("psctl: PSCTL_STAT: [%" PRIiPID "]", pid);
+			return;
+		}
+		char* path_string = get_program_path_of_pid(pid);
+		const char* path = last_basename(path_string ? path_string : "<unknown>");
+		if ( !continuation )
+			fputs(prefix, stdout);
+		if ( prefix[0] )
+		{
+			if ( continuation )
+				fputs("─", stdout);
+			else
+				fputs(" ", stdout);
+			if ( continuation )
+				fputs(psst.ppid_next == -1 ? "─" : "┬", stdout);
+			else
+				fputs(psst.ppid_next == -1 ? "└" : "│", stdout);
+			fputs("─", stdout);
+		}
+		printf("%s", path);
+		if ( psst.ppid_first != -1 )
+		{
+			size_t path_length = strlen(path);
+			char* new_prefix;
+			if ( prefix[0] )
+			{
+				size_t prefix_length = strlen(prefix);
+				size_t new_prefix_length = prefix_length + 3 + path_length;
+				if ( !(new_prefix = (char*) malloc(new_prefix_length + 1)) )
+					err(1, "malloc");
+				memcpy(new_prefix, prefix, prefix_length);
+				memcpy(new_prefix + prefix_length,
+					   psst.ppid_next != -1 ? " | " : "   ", 3);
+				for ( size_t i = 0; i < path_length; i++ )
+					new_prefix[prefix_length + 3 + i] = ' ';
+				new_prefix[prefix_length + 3 + path_length] = '\0';
+			}
+			else
+			{
+				if ( !(new_prefix = (char*) malloc(path_length + 1)) )
+					err(1, "malloc");
+				for ( size_t i = 0; i < path_length; i++ )
+					new_prefix[i] = ' ';
+				new_prefix[path_length] = '\0';
+			}
+			pstree(psst.ppid_first, new_prefix, true);
+			free(new_prefix);
+		}
+		else
+			printf("\n");
+		free(path_string);
+		continuation = false;
+		pid = psst.ppid_next;
+	}
+}
+
+static void compact_arguments(int* argc, char*** argv)
+{
+	for ( int i = 0; i < *argc; i++ )
+	{
+		while ( i < *argc && !(*argv)[i] )
+		{
+			for ( int n = i; n < *argc; n++ )
+				(*argv)[n] = (*argv)[n+1];
+			(*argc)--;
+		}
+	}
+}
+
+static void help(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "Usage: %s [OPTION]...\n", argv0);
+	fprintf(fp, "List processes.\n");
+}
+
+static void version(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
+	fprintf(fp, "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.\n");
+	fprintf(fp, "This is free software: you are free to change and redistribute it.\n");
+	fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n");
+}
+
+int main(int argc, char* argv[])
+{
+	setlocale(LC_ALL, "");
+
+	const char* argv0 = argv[0];
+	for ( int i = 1; i < argc; i++ )
+	{
+		const char* arg = argv[i];
+		if ( arg[0] != '-' || !arg[1] )
+			continue;
+		argv[i] = NULL;
+		if ( !strcmp(arg, "--") )
+			break;
+		if ( arg[1] != '-' )
+		{
+			while ( char c = *++arg ) switch ( c )
+			{
+			default:
+				fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
+				help(stderr, argv0);
+				exit(1);
+			}
+		}
+		else if ( !strcmp(arg, "--help") )
+			help(stdout, argv0), exit(0);
+		else if ( !strcmp(arg, "--version") )
+			version(stdout, argv0), exit(0);
+		else
+		{
+			fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
+			help(stderr, argv0);
+			exit(1);
+		}
+	}
+
+	compact_arguments(&argc, &argv);
+
+	if ( 1 < argc )
+		err(1, "extra operand: %s", argv[1]);
+
+	pstree(1, "", true);
+
+	return ferror(stdout) || fflush(stdout) == EOF ? 1 : 0;
+}