diff --git a/hw/rtc/Kconfig b/hw/rtc/Kconfig
index 45daa8d..3dc2dd6 100644
--- a/hw/rtc/Kconfig
+++ b/hw/rtc/Kconfig
@@ -17,6 +17,7 @@
     depends on I2C
 
 config MC146818RTC
+    depends on ISA_BUS
     bool
 
 config SUN4V_RTC