diff --git a/soc/arm/nordic_nrf/nrf51/Kconfig.defconfig.nrf51822_QFAA b/soc/arm/nordic_nrf/nrf51/Kconfig.defconfig.nrf51822_QFAA
index 311dab6fc15..7644e5f39a3 100644
--- a/soc/arm/nordic_nrf/nrf51/Kconfig.defconfig.nrf51822_QFAA
+++ b/soc/arm/nordic_nrf/nrf51/Kconfig.defconfig.nrf51822_QFAA
@@ -9,7 +9,4 @@ if SOC_NRF51822_QFAA
 config SOC
 	default "nRF51822_QFAA"
 
-config ISR_STACK_SIZE
-	default 640
-
 endif # SOC_NRF51822_QFAA
diff --git a/soc/arm/nordic_nrf/nrf51/Kconfig.defconfig.nrf51822_QFAB b/soc/arm/nordic_nrf/nrf51/Kconfig.defconfig.nrf51822_QFAB
index 68990ab20f8..6678f846e36 100644
--- a/soc/arm/nordic_nrf/nrf51/Kconfig.defconfig.nrf51822_QFAB
+++ b/soc/arm/nordic_nrf/nrf51/Kconfig.defconfig.nrf51822_QFAB
@@ -9,7 +9,4 @@ if SOC_NRF51822_QFAB
 config SOC
 	default "nRF51822_QFAB"
 
-config ISR_STACK_SIZE
-	default 640
-
 endif # SOC_NRF51822_QFAB