diff --git a/testing/scripts/check_static_initializers.py b/testing/scripts/check_static_initializers.py
index 140744aa39f98e..2d93d4f30cfc23 100755
--- a/testing/scripts/check_static_initializers.py
+++ b/testing/scripts/check_static_initializers.py
@@ -57,11 +57,12 @@
 
 # Two static initializers are needed on Mac for libc++ to set up
 # std::cin/cout/cerr before main() runs. Only iostream.cpp needs to be counted
-# here.
-FALLBACK_EXPECTED_MAC_SI_COUNT = 2
+# here. Plus, PartitionAlloc-Everywhere uses one static initializer
+# (InitializeDefaultMallocZoneWithPartitionAlloc) to install a malloc zone.
+FALLBACK_EXPECTED_MAC_SI_COUNT = 3
 
 # For coverage builds, also allow 'IntrProfilingRuntime.cpp'
-COVERAGE_BUILD_FALLBACK_EXPECTED_MAC_SI_COUNT = 3
+COVERAGE_BUILD_FALLBACK_EXPECTED_MAC_SI_COUNT = 4
 
 
 def run_process(command):