diff --git a/pkg/sentry/fsimpl/cgroupfs/base.go b/pkg/sentry/fsimpl/cgroupfs/base.go
index f70734d7d..c3209573d 100644
--- a/pkg/sentry/fsimpl/cgroupfs/base.go
+++ b/pkg/sentry/fsimpl/cgroupfs/base.go
@@ -363,7 +363,13 @@ func (d *cgroupProcsData) Write(ctx context.Context, fd *vfs.FileDescription, sr
 
 	t := kernel.TaskFromContext(ctx)
 	currPidns := t.ThreadGroup().PIDNamespace()
-	targetTG := currPidns.ThreadGroupWithID(kernel.ThreadID(tgid))
+	var targetTG *kernel.ThreadGroup
+	if tgid != 0 {
+		targetTG = currPidns.ThreadGroupWithID(kernel.ThreadID(tgid))
+	} else {
+		targetTG = t.ThreadGroup()
+	}
+
 	if targetTG == nil {
 		return 0, linuxerr.EINVAL
 	}
@@ -405,7 +411,12 @@ func (d *tasksData) Write(ctx context.Context, fd *vfs.FileDescription, src user
 
 	t := kernel.TaskFromContext(ctx)
 	currPidns := t.ThreadGroup().PIDNamespace()
-	targetTask := currPidns.TaskWithID(kernel.ThreadID(tid))
+	var targetTask *kernel.Task
+	if tid != 0 {
+		targetTask = currPidns.TaskWithID(kernel.ThreadID(tid))
+	} else {
+		targetTask = t
+	}
 	if targetTask == nil {
 		return 0, linuxerr.EINVAL
 	}
diff --git a/test/syscalls/linux/cgroup.cc b/test/syscalls/linux/cgroup.cc
index 812c10c94..fc34bcd11 100644
--- a/test/syscalls/linux/cgroup.cc
+++ b/test/syscalls/linux/cgroup.cc
@@ -549,6 +549,42 @@ TEST(Cgroup, Rename) {
   EXPECT_THAT(Exists(child.Relpath("oldname")), IsPosixErrorOkAndHolds(false));
 }
 
+TEST(Cgroup, PIDZeroMovesSelf) {
+  SKIP_IF(!CgroupsAvailable());
+  Mounter m(ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir()));
+  Cgroup c = ASSERT_NO_ERRNO_AND_VALUE(m.MountCgroupfs(""));
+  Cgroup child = ASSERT_NO_ERRNO_AND_VALUE(c.CreateChild("child"));
+
+  // Source contains this process.
+  EXPECT_NO_ERRNO(c.ContainsCallingProcess());
+
+  // Move to child by writing PID 0.
+  ASSERT_NO_ERRNO(child.WriteIntegerControlFile("cgroup.procs", 0));
+
+  // Destination now contains this process, and source does not.
+  EXPECT_NO_ERRNO(child.ContainsCallingProcess());
+  auto procs = ASSERT_NO_ERRNO_AND_VALUE(c.Procs());
+  EXPECT_FALSE(procs.contains(getpid()));
+}
+
+TEST(Cgroup, TIDZeroMovesSelf) {
+  SKIP_IF(!CgroupsAvailable());
+  Mounter m(ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir()));
+  Cgroup c = ASSERT_NO_ERRNO_AND_VALUE(m.MountCgroupfs(""));
+  Cgroup child = ASSERT_NO_ERRNO_AND_VALUE(c.CreateChild("child"));
+
+  // Source contains this thread.
+  EXPECT_NO_ERRNO(c.ContainsCallingThread());
+
+  // Move to child by writing TID 0.
+  ASSERT_NO_ERRNO(child.WriteIntegerControlFile("tasks", 0));
+
+  // Destination now contains this thread, and source does not.
+  EXPECT_NO_ERRNO(child.ContainsCallingThread());
+  auto tasks = ASSERT_NO_ERRNO_AND_VALUE(c.Tasks());
+  EXPECT_FALSE(tasks.contains(syscall(SYS_gettid)));
+}
+
 TEST(MemoryCgroup, MemoryUsageInBytes) {
   SKIP_IF(!CgroupsAvailable());