diff --git a/Cargo.toml b/Cargo.toml
index 3f05fa9a2..a2451c352 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -81,7 +81,9 @@ globset = "0.4"
 junction = { version = "2.1.0", default-features = false }
 keyring = { version = "3.6.3", default-features = false }
 # Python loads the extension with dlopen, so mimalloc must not use initial-exec TLS.
-mimalloc = { version = "0.1", default-features = false, features = ["local_dynamic_tls"] }
+# no_thp: mimalloc otherwise asks for transparent huge pages on its 1 GiB arenas, and each
+# partly used 2 MiB page then stays resident in full, which raises peak memory.
+mimalloc = { version = "0.1", default-features = false, features = ["local_dynamic_tls", "no_thp"] }
 proc-macro2 = { version = "1", features = ["span-locations"] }
 pyo3 = { version = "0.26", features = ["abi3-py312"] }
 rpassword = "7.5.4"