diff --git a/core/siren-core-env.el b/core/siren-core-env.el
index d65f8f6..f55c865 100644
--- a/core/siren-core-env.el
+++ b/core/siren-core-env.el
@@ -14,6 +14,7 @@
                                     "TMPDIR"
                                     "KUBECONFIG"
                                     "GOPRIVATE"
+                                    "LSP_USE_PLISTS"
                                     "RUST_BACKTRACE"
                                     "MallocNanoZone"))
   (exec-path-from-shell-arguments '("-l"))
diff --git a/early-init.el b/early-init.el
index 8d6c03f..c910a02 100644
--- a/early-init.el
+++ b/early-init.el
@@ -53,4 +53,7 @@
 ;; larger than the system default.
 (setq frame-inhibit-implied-resize t)
 
+;; Set lsp-mode to use plists for performance improvements.
+(setenv "LSP_USE_PLISTS" "true")
+
 ;;; early-init.el ends here