diff --git a/clap_mangen/src/lib.rs b/clap_mangen/src/lib.rs
index 7b8d8af79004..b9fbdb76d1ad 100644
--- a/clap_mangen/src/lib.rs
+++ b/clap_mangen/src/lib.rs
@@ -258,7 +258,11 @@ impl Man {
     fn _render_subcommands_section(&self, roff: &mut Roff) {
         let heading = subcommand_heading(&self.cmd);
         roff.control("SH", [heading]);
-        render::subcommands(roff, &self.cmd, &self.section);
+        if self.cmd.is_flatten_help_set() {
+            render::flat_subcommands(roff, &self.cmd);
+        } else {
+            render::subcommands(roff, &self.cmd, &self.section);
+        }
     }
 
     /// Render the EXTRA section into the writer.
diff --git a/clap_mangen/src/render.rs b/clap_mangen/src/render.rs
index 009750a7ff03..4b0dda74558a 100644
--- a/clap_mangen/src/render.rs
+++ b/clap_mangen/src/render.rs
@@ -30,21 +30,46 @@ pub(crate) fn description(roff: &mut Roff, cmd: &clap::Command) {
 }
 
 pub(crate) fn synopsis(roff: &mut Roff, cmd: &clap::Command) {
-    let name = cmd.get_bin_name().unwrap_or_else(|| cmd.get_name());
-    let mut line = vec![bold(name), roman(" ")];
-    let mut line = usage(cmd, name);
-
-    if cmd.has_subcommands() && !flatten {
-        let (lhs, rhs) = subcommand_markers(cmd);
-        line.push(roman(lhs));
-        line.push(italic(
-            cmd.get_subcommand_value_name()
-                .unwrap_or_else(|| subcommand_heading(cmd))
-                .to_lowercase(),
+    let flatten = cmd.is_flatten_help_set();
+
+    let mut ord_v = Vec::new();
+    if flatten {
+        for subcommand in cmd.get_subcommands() {
+            ord_v.push((
+                subcommand.get_display_order(),
+                subcommand.get_bin_name().unwrap_or_else(|| cmd.get_name()),
+                subcommand,
+            ));
+        }
+        ord_v.sort_by(|a, b| (a.0, &a.1).cmp(&(b.0, &b.1)));
+    } else {
+        ord_v.push((
+            cmd.get_display_order(),
+            cmd.get_bin_name().unwrap_or_else(|| cmd.get_name()),
+            cmd,
         ));
-        line.push(roman(rhs));
     }
-    roff.text(line);
+
+    let mut first = true;
+    for (_, name, cmd) in ord_v {
+        if !first && flatten {
+            roff.control("br", []);
+        } else {
+            first = false;
+        }
+        let mut line = usage(cmd, name);
+
+        if cmd.has_subcommands() && !flatten {
+            let (lhs, rhs) = subcommand_markers(cmd);
+            line.push(roman(lhs));
+            line.push(italic(
+                cmd.get_subcommand_value_name()
+                    .unwrap_or_else(|| subcommand_heading(cmd))
+                    .to_lowercase(),
+            ));
+            line.push(roman(rhs));
+        }
+        roff.text(line);
     }
 }
 
@@ -226,6 +251,26 @@ pub(crate) fn subcommands(roff: &mut Roff, cmd: &clap::Command, section: &str) {
     }
 }
 
+pub(crate) fn flat_subcommands(roff: &mut Roff, cmd: &clap::Command) {
+    for sub in cmd.get_subcommands().filter(|s| !s.is_hide_set()) {
+        roff.control("TP", []);
+
+        let mut line = usage(sub, sub.get_name());
+
+        if let Some(about) = sub.get_long_about().or_else(|| sub.get_about()) {
+            line.push(roman("\n"));
+            line.push(roman(about.to_string()));
+        }
+
+        if let Some(after_help) = sub.get_after_help() {
+            line.push(roman("\n"));
+            line.push(roman(after_help.to_string()));
+        }
+
+        roff.text(line);
+    }
+}
+
 pub(crate) fn version(cmd: &clap::Command) -> String {
     format!(
         "v{}",
diff --git a/clap_mangen/tests/snapshots/flatten_help.roff b/clap_mangen/tests/snapshots/flatten_help.roff
index e9ab64a9d6fc..e2dd9cc9a9f1 100644
--- a/clap_mangen/tests/snapshots/flatten_help.roff
+++ b/clap_mangen/tests/snapshots/flatten_help.roff
@@ -4,7 +4,9 @@
 .SH NAME
 my\-app
 .SH SYNOPSIS
-\fBmy\-app\fR [\fB\-c \fR] [\fB\-v \fR] [\fB\-h\fR|\fB\-\-help\fR] [\fIsubcommands\fR]
+\fBmy\-app test\fR [\fB\-d \fR]... [\fB\-c \fR] [\fB\-h\fR|\fB\-\-help\fR] 
+.br
+\fBmy\-app help\fR 
 .SH DESCRIPTION
 .SH OPTIONS
 .TP
@@ -18,9 +20,9 @@ my\-app
 Print help
 .SH SUBCOMMANDS
 .TP
-my\-app\-test(1)
+\fBtest\fR [\fB\-d \fR]... [\fB\-c \fR] [\fB\-h\fR|\fB\-\-help\fR] 
 Subcommand
 with a second line
 .TP
-my\-app\-help(1)
+\fBhelp\fR 
 Print this message or the help of the given subcommand(s)