diff --git a/libc/Android.mk b/libc/Android.mk
index 229de77..0d3e2c3 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -26,6 +26,7 @@
 	unistd/initgroups.c \
 	unistd/isatty.c \
 	unistd/issetugid.c \
+	unistd/killpg.c \
 	unistd/lseek64.c \
 	unistd/mmap.c \
 	unistd/nice.c \
diff --git a/libc/include/signal.h b/libc/include/signal.h
index 5540847..9e5ce61 100644
--- a/libc/include/signal.h
+++ b/libc/include/signal.h
@@ -118,6 +118,7 @@
 
 extern int raise(int);
 extern int kill(pid_t, int);
+extern int killpg(int pgrp, int sig);
 
 
 __END_DECLS
diff --git a/libc/unistd/killpg.c b/libc/unistd/killpg.c
new file mode 100644
index 0000000..75b1ad9
--- /dev/null
+++ b/libc/unistd/killpg.c
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 1989 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * 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.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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/types.h>
+#include <signal.h>
+#include <errno.h>
+
+/*
+ * Backwards-compatible killpg().
+ */
+int
+killpg(pid_t pgid, int sig)
+{
+	if (pgid == 1) {
+		errno = ESRCH;
+		return (-1);
+	}
+	return (kill(-pgid, sig));
+}