diff --git a/src/kontrol/cli.py b/src/kontrol/cli.py
index 559bdff29..d53514e40 100644
--- a/src/kontrol/cli.py
+++ b/src/kontrol/cli.py
@@ -289,6 +289,13 @@ def parse(s: str) -> list[T]:
             config_args.config_args,
         ],
     )
+    build.add_argument(
+        '--no-O2',
+        dest='o2',
+        default=None,
+        action='store_false',
+        help='Do not use optimization level 2.',
+    )
     build.add_argument(
         '--regen',
         dest='regen',
diff --git a/src/kontrol/options.py b/src/kontrol/options.py
index 016be5706..d86b01b36 100644
--- a/src/kontrol/options.py
+++ b/src/kontrol/options.py
@@ -858,6 +858,7 @@ class BuildOptions(LoggingOptions, KOptions, KGenOptions, KompileOptions, Foundr
     @staticmethod
     def default() -> dict[str, Any]:
         return {
+            'o2': True,
             'regen': False,
             'rekompile': False,
             'forge_build': True,
diff --git a/src/kontrol/utils.py b/src/kontrol/utils.py
index c3efab309..d84254a54 100644
--- a/src/kontrol/utils.py
+++ b/src/kontrol/utils.py
@@ -209,6 +209,7 @@ def kontrol_toml_file_contents() -> str:
 require                    = 'lemmas.k'
 module-import              = 'TestBase:KONTROL-LEMMAS'
 auxiliary-lemmas           = true
+o2                         = true
 
 [prove.default]
 foundry-project-root       = '.'