diff --git a/NAMESPACE b/NAMESPACE
index d33f43bc..ebb8c637 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -53,6 +53,7 @@ export(ps_shared_lib_users)
 export(ps_shared_libs)
 export(ps_status)
 export(ps_suspend)
+export(ps_switch_to)
 export(ps_system_cpu_times)
 export(ps_system_memory)
 export(ps_system_swap)
diff --git a/R/windows.R b/R/windows.R
new file mode 100644
index 00000000..70b4d4f4
--- /dev/null
+++ b/R/windows.R
@@ -0,0 +1,60 @@
+
+#' Send an alert to the window of a process
+#'
+#' This function currently only works on Windows and errors on
+#' other platforms.
+#'
+#' R processes might not have an associated window, e.g. if they are
+#' running in a terminal, or in RStudio. In RGui they do.
+#'
+#' @param p Process handle.
+#' @param ancestors Logical flag. Whether to try to alert the
+#' closest ancestor in the process tree, if the specified process
+#' does not have an associated window. It uses [ps_descent()] to
+#' look up the ancestors.
+#' @return A named list:
+#' * `proc`: a process handle. This is the handle that ps tried to
+#'   alert. It might that same as `p` or an ancestor, if
+#'   `ancestors = TRUE` was specified. This is `NULL` if ps did
+#'   not find any process with an associated Window to alert.
+#' * `success`: whether the Windows API call returned success.
+#'   If this is `TRUE` that typically means that the alerted
+#'   window is the active one. If it is `FALSE`, then the alert was
+#'   probably still sent, and the user will see it on the status bar
+#'   (in Windows 10).
+#'
+#' @export
+#' @examples
+#' \dontrun{
+#' # This usually does nothing interactively, since the current
+#' # (RStudio, RGui, Windows Terminal, etc.) window is on top.
+#' ps_switch_to()
+#'
+#' # Try switching to another window, while the sleep is running,
+#' # and then you'll see an alert for the current
+#' # (RStudio, RGui, etc.) window
+#' Sys.sleep(4); ps_switch_to()
+#' }
+
+ps_switch_to <- function(p = ps_handle(), ancestors = TRUE) {
+  os <- ps_os_type()
+  if (!os[["WINDOWS"]]) {
+    stop("`ps_windows()` currently only works on Windows")
+  }
+  assert_ps_handle(p)
+
+  if (ancestors) {
+    plist <- ps_descent(p)
+  } else {
+    plist <- list(p)
+  }
+  pids <- map_int(plist, ps_pid)
+
+  ret <- .Call(psll_switch_to, pids)
+  if (ret == 0) {
+    list(proc = NULL, success = FALSE)
+  } else {
+    # -pid on failure
+    list(proc = plist[[match(abs(ret), pids)]], success = ret > 0)
+  }
+}
diff --git a/_pkgdown.yml b/_pkgdown.yml
index 3fa4441d..0186d2a9 100644
--- a/_pkgdown.yml
+++ b/_pkgdown.yml
@@ -59,6 +59,7 @@ reference:
   - ps_set_cpu_affinity
   - ps_get_nice
   - ps_set_nice
+  - ps_switch_to
   - ps_wait
   - ps_windows_nice_values
 
diff --git a/man/ps_switch_to.Rd b/man/ps_switch_to.Rd
new file mode 100644
index 00000000..b1fc70b8
--- /dev/null
+++ b/man/ps_switch_to.Rd
@@ -0,0 +1,50 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/windows.R
+\name{ps_switch_to}
+\alias{ps_switch_to}
+\title{Send an alert to the window of a process}
+\usage{
+ps_switch_to(p = ps_handle(), ancestors = TRUE)
+}
+\arguments{
+\item{p}{Process handle.}
+
+\item{ancestors}{Logical flag. Whether to try to alert the
+closest ancestor in the process tree, if the specified process
+does not have an associated window. It uses \code{\link[=ps_descent]{ps_descent()}} to
+look up the ancestors.}
+}
+\value{
+A named list:
+\itemize{
+\item \code{proc}: a process handle. This is the handle that ps tried to
+alert. It might that same as \code{p} or an ancestor, if
+\code{ancestors = TRUE} was specified. This is \code{NULL} if ps did
+not find any process with an associated Window to alert.
+\item \code{success}: whether the Windows API call returned success.
+If this is \code{TRUE} that typically means that the alerted
+window is the active one. If it is \code{FALSE}, then the alert was
+probably still sent, and the user will see it on the status bar
+(in Windows 10).
+}
+}
+\description{
+This function currently only works on Windows and errors on
+other platforms.
+}
+\details{
+R processes might not have an associated window, e.g. if they are
+running in a terminal, or in RStudio. In RGui they do.
+}
+\examples{
+\dontrun{
+# This usually does nothing interactively, since the current
+# (RStudio, RGui, Windows Terminal, etc.) window is on top.
+ps_switch_to()
+
+# Try switching to another window, while the sleep is running,
+# and then you'll see an alert for the current
+# (RStudio, RGui, etc.) window
+Sys.sleep(4); ps_switch_to()
+}
+}
diff --git a/src/api-windows.c b/src/api-windows.c
index 8f434005..36d15cba 100644
--- a/src/api-windows.c
+++ b/src/api-windows.c
@@ -1740,7 +1740,69 @@ SEXP psll_set_nice(SEXP p, SEXP value) {
   if (hProcess) CloseHandle(hProcess);
   ps__throw_error();
   return R_NilValue;
+}
+
+struct psll_windows_data {
+  int *pids;
+  int num_pids;
+  HWND handle;
+  SEXP result;
+};
+
+BOOL CALLBACK psll_switch_to_proc1(
+    _In_ HWND   hwnd,
+    _In_ LPARAM lParam) {
+  struct psll_windows_data *data = (struct psll_windows_data*) lParam;
+
+  DWORD processId;
+  DWORD ret = GetWindowThreadProcessId(hwnd, &processId);
+  if (!ret) return TRUE;
+
+  int i;
+  for (i = 0; i < data->num_pids; i++) {
+    if (data->pids[i] == processId) {
+      data->handle = hwnd;
+      data->num_pids = i;
+      INTEGER(data->result)[0] = processId;
+      if (i == 0) return FALSE; else return TRUE;
+    }
+  }
+
+  return TRUE;
+}
+
+BOOL CALLBACK psll_switch_to_proc2(
+    _In_ HWND   hwnd,
+    _In_ LPARAM lParam) {
+  struct psll_windows_data *data = (struct psll_windows_data*) lParam;
 
+  if (hwnd == data->handle) {
+    BOOL ret = SetForegroundWindow(hwnd);
+    if (!ret) {
+      INTEGER(data->result)[0] = -INTEGER(data->result)[0];
+    }
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+SEXP psll_switch_to(SEXP pids) {
+  struct psll_windows_data data;
+  data.pids = INTEGER(pids);
+  data.num_pids = LENGTH(pids);
+  data.handle = NULL;
+  data.result = PROTECT(allocVector(INTSXP, 1));
+  INTEGER(data.result)[0] = 0;
+
+  EnumWindows(psll_switch_to_proc1, (LPARAM) &data);
+
+  if (data.handle != NULL) {
+    EnumWindows(psll_switch_to_proc2, (LPARAM) &data);
+  }
+
+  UNPROTECT(1);
+  return data.result;
 }
 
 
diff --git a/src/dummy.c b/src/dummy.c
index a76929ac..929820a8 100644
--- a/src/dummy.c
+++ b/src/dummy.c
@@ -50,6 +50,7 @@ SEXP psp__stat_st_rdev(SEXP x) { return ps__dummy("psp__stat_st_rdev"); }
 #ifndef PS__WINDOWS
 SEXP psw__realpath(SEXP x) { return ps__dummy("psw__realpath"); }
 SEXP psll_dlls(SEXP x) { return ps__dummy("psll_dlls"); }
+SEXP psll_switch_to(SEXP x) { return ps__dummy("psll_switch_to"); }
 #endif
 #endif
 
diff --git a/src/init.c b/src/init.c
index 3eecc9e9..7ea79e1d 100644
--- a/src/init.c
+++ b/src/init.c
@@ -69,6 +69,7 @@ static const R_CallMethodDef callMethods[]  = {
   { "psll_get_nice",     (DL_FUNC) psll_get_nice,     1 },
   { "psll_set_nice",     (DL_FUNC) psll_set_nice,     2 },
   { "psll_dlls",         (DL_FUNC) psll_dlls,         1 },
+  { "psll_switch_to",    (DL_FUNC) psll_switch_to,    1 },
   { "psll_get_cpu_aff",  (DL_FUNC) psll_get_cpu_aff,  1 },
   { "psll_set_cpu_aff",  (DL_FUNC) psll_set_cpu_aff,  2 },
   { "psll_wait",         (DL_FUNC) psll_wait,         2 },
diff --git a/src/ps.h b/src/ps.h
index b026f1f7..a98975dd 100644
--- a/src/ps.h
+++ b/src/ps.h
@@ -44,6 +44,7 @@ SEXP psll_connections(SEXP p);
 SEXP psll_get_nice(SEXP p);
 SEXP psll_set_nice(SEXP p, SEXP value);
 SEXP psll_dlls(SEXP p);
+SEXP psll_switch_to(SEXP plist);
 SEXP psll_get_cpu_aff(SEXP p);
 SEXP psll_set_cpu_aff(SEXP p, SEXP affinity);
 SEXP psll_wait(SEXP p, SEXP timeout);