diff --git a/cli/src/cli_util.rs b/cli/src/cli_util.rs
index 103ea17322..92b07ce278 100644
--- a/cli/src/cli_util.rs
+++ b/cli/src/cli_util.rs
@@ -23,7 +23,7 @@ use std::path::{Path, PathBuf};
 use std::process::ExitCode;
 use std::rc::Rc;
 use std::str::FromStr;
-use std::sync::Arc;
+use std::sync::{Arc, OnceLock};
 use std::time::SystemTime;
 use std::{fs, str};
 
@@ -31,6 +31,7 @@ use clap::builder::{NonEmptyStringValueParser, TypedValueParser, ValueParserFact
 use clap::{Arg, ArgAction, ArgMatches, Command, FromArgMatches};
 use indexmap::{IndexMap, IndexSet};
 use itertools::Itertools;
+use jj_cbits::mimalloc;
 use jj_lib::backend::{ChangeId, CommitId, MergedTreeId};
 use jj_lib::commit::Commit;
 use jj_lib::git_backend::GitBackend;
@@ -2151,6 +2152,57 @@ pub struct EarlyArgs {
     pub config_toml: Vec<String>,
 }
 
+#[derive(clap::Args, Clone, Debug)]
+pub struct ShowAllocStats {
+    /// Show memory allocation statistics from the internal heap allocator
+    /// on `stdout`, when the program exits.
+    #[arg(long, global = true)]
+    show_heap_stats: bool,
+}
+
+/// Lazy global static. Used only to defer printing mimalloc stats until the
+/// program exits, if set to `true`.
+static PRINT_HEAP_STATS: OnceLock<bool> = OnceLock::new();
+
+/// Enable heap statistics for the user interface; should be used with
+/// [`CliRunner::add_global_args`]. Does nothing if the memory allocator is
+/// unused, i.e. `#[global_allocator]` is not set to mimalloc in your program.
+pub fn heap_stats_enable(_ui: &mut Ui, opts: ShowAllocStats) -> Result<(), CommandError> {
+    if opts.show_heap_stats {
+        PRINT_HEAP_STATS.set(true).unwrap();
+    }
+    Ok(())
+}
+
+/// Reset heap allocation statistics for the memory allocator. Often used at the
+/// very beginning of the program (to clear allocations that may happen before
+/// `_main` execution.)
+pub fn heap_stats_reset() {
+    mimalloc::stats_reset();
+}
+
+/// Print heap allocation statistics to `stderr`, if enabled.
+pub fn heap_stats_print() {
+    // NOTE (aseipp): can we do our own custom printing here? it's kind of ugly
+    if PRINT_HEAP_STATS.get() == Some(&true) {
+        eprintln!("========================================");
+        eprintln!("mimalloc memory allocation statistics:\n");
+        mimalloc::stats_print(&|l| {
+            eprint!("{}", l.to_string_lossy());
+        });
+    }
+}
+
+/// Wrap a given closure with calls to [`heap_stats_reset`] and
+/// [`heap_stats_print`], and return the result of the closure. Useful for
+/// conveiently printing heap allocation statistics for a given function body.
+pub fn heap_stats_with_closure<R>(f: impl FnOnce() -> R) -> R {
+    heap_stats_reset();
+    let result = f();
+    heap_stats_print();
+    result
+}
+
 /// Create a description from a list of paragraphs.
 ///
 /// Based on the Git CLI behavior. See `opt_parse_m()` and `cleanup_mode` in
diff --git a/cli/src/main.rs b/cli/src/main.rs
index 38ea1a6870..07a9cc3c5e 100644
--- a/cli/src/main.rs
+++ b/cli/src/main.rs
@@ -12,12 +12,19 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! Primary entrypoint for the stock `jj` command-line tool. mimalloc enabled.
+
 use jj_cbits::mimalloc::MiMalloc;
-use jj_cli::cli_util::CliRunner;
+use jj_cli::cli_util::{heap_stats_enable, heap_stats_with_closure, CliRunner};
 
 #[global_allocator]
 static ALLOC: MiMalloc = MiMalloc;
 
 fn main() -> std::process::ExitCode {
-    CliRunner::init().version(env!("JJ_VERSION")).run()
+    heap_stats_with_closure(|| {
+        CliRunner::init()
+            .add_global_args(heap_stats_enable)
+            .version(env!("JJ_VERSION"))
+            .run()
+    })
 }
diff --git a/cli/tests/cli-reference@.md.snap b/cli/tests/cli-reference@.md.snap
index 82a27bfc24..9039562ba9 100644
--- a/cli/tests/cli-reference@.md.snap
+++ b/cli/tests/cli-reference@.md.snap
@@ -163,6 +163,10 @@ repository.
   Possible values: `true`, `false`
 
 * `--config-toml <TOML>` — Additional configuration options (can be repeated)
+* `--show-heap-stats` — Show memory allocation statistics from the internal heap allocator on `stdout`, when the program exits
+
+  Possible values: `true`, `false`
+
 
 
 
diff --git a/cli/tests/test_global_opts.rs b/cli/tests/test_global_opts.rs
index 3596460ed9..533cc92243 100644
--- a/cli/tests/test_global_opts.rs
+++ b/cli/tests/test_global_opts.rs
@@ -451,6 +451,8 @@ fn test_help() {
           --color <WHEN>                 When to colorize output (always, never, auto)
           --no-pager                     Disable the pager
           --config-toml <TOML>           Additional configuration options (can be repeated)
+          --show-heap-stats              Show memory allocation statistics from the internal heap
+                                         allocator on `stdout`, when the program exits
     "###);
 }