diff --git a/tests/unittests/tests-rtt_rtc/Makefile.include b/tests/unittests/tests-rtt_rtc/Makefile.include
index c3d957baf7..12c335ba09 100644
--- a/tests/unittests/tests-rtt_rtc/Makefile.include
+++ b/tests/unittests/tests-rtt_rtc/Makefile.include
@@ -6,3 +6,7 @@ CFLAGS += -DMOCK_RTT_MAX_VALUE=0xFFFF
 # mulle always enables periph_rtt.
 # This clashes with mock_rtt.
 BOARD_BLACKLIST := mulle
+
+# esp32 enables periph_rtc by default.
+# This clashes with rtt_rtc,
+FEATURES_BLACKLIST += arch_esp32