diff --git a/BaseTools/Plugin/HostBasedUnitTestRunner/HostBasedUnitTestRunner.py b/BaseTools/Plugin/HostBasedUnitTestRunner/HostBasedUnitTestRunner.py
index 31d13b2ee7782..9fb8a19c6da23 100644
--- a/BaseTools/Plugin/HostBasedUnitTestRunner/HostBasedUnitTestRunner.py
+++ b/BaseTools/Plugin/HostBasedUnitTestRunner/HostBasedUnitTestRunner.py
@@ -156,7 +156,8 @@ def gen_code_coverage_gcc(self, thebuilder):
             return 1
 
         # Coverage data for tested files only
-        ret = RunCmd("lcov", f"--capture --directory {buildOutputBase}/ --output-file {buildOutputBase}/coverage-test.info --rc lcov_branch_coverage=1")
+        # `--ignore-errors mismatch` needed to make lcov v2.0+/gcov work.
+        ret = RunCmd("lcov", f"--capture --directory {buildOutputBase}/ --output-file {buildOutputBase}/coverage-test.info --rc lcov_branch_coverage=1 --ignore-errors mismatch")
         if ret != 0:
             logging.error("UnitTest Coverage: Failed to build coverage data for tested files.")
             return 1