diff --git a/.github/workflows/test-on-iotlab.yml b/.github/workflows/test-on-iotlab.yml
index 99249fe94df1..6932408d1007 100644
--- a/.github/workflows/test-on-iotlab.yml
+++ b/.github/workflows/test-on-iotlab.yml
@@ -82,6 +82,10 @@ jobs:
       #   but flashing at a specific offset is not (yet) supported on IoT-LAB
       #   so it will always fail because of that limitation
       APPLICATIONS_EXCLUDE: tests/periph_timer_short_relative_set tests/riotboot
+      # Increase tolerance error with `tests/periph_timer_periodic` because
+      # of timing issues with the test script when running in the github
+      # actions environment
+      TEST_PERIPH_TIMER_PERIODIC_PRECISION: 0.30
     steps:
       - name: Set up Python 3.8
         uses: actions/setup-python@v2
diff --git a/tests/periph_timer_periodic/tests/01-run.py b/tests/periph_timer_periodic/tests/01-run.py
index ac28e2f79780..653914f86e32 100755
--- a/tests/periph_timer_periodic/tests/01-run.py
+++ b/tests/periph_timer_periodic/tests/01-run.py
@@ -6,19 +6,24 @@
 # General Public License v2.1. See the file LICENSE in the top level
 # directory for more details.
 
+import os
 import sys
 import time
 from testrunner import run
 
 
+PRECISION = float(os.getenv("TEST_PERIPH_TIMER_PERIODIC_PRECISION", "0"))
+
+
 def testfunc(child):
     child.expect_exact('TEST START')
     start = time.time()
     child.expect_exact('TEST SUCCEEDED')
     end = time.time()
     # test should run 10 cycles with 25ms each
-    assert (end - start) > 0.25
-    assert (end - start) < 0.40
+    elapsed = end - start
+    assert elapsed > 0.25 * (1 - PRECISION), "=< 0.25s ({})".format(elapsed)
+    assert elapsed < 0.40 * (1 + PRECISION), "=> 0.40s ({})".format(elapsed)
 
 
 if __name__ == "__main__":