diff --git a/src/RTCZero.cpp b/src/RTCZero.cpp
index 593a8bb..e322d0f 100644
--- a/src/RTCZero.cpp
+++ b/src/RTCZero.cpp
@@ -145,11 +145,15 @@ void RTCZero::detachInterrupt()
 
 void RTCZero::standbyMode()
 {
+  // Disable systick interrupt
+  SysTick->CTRL &= ~SysTick_CTRL_TICKINT_Msk;
   // Entering standby mode when connected
   // via the native USB port causes issues.
   SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
   __DSB();
   __WFI();
+  // Enable systick interrupt
+  SysTick->CTRL |= SysTick_CTRL_TICKINT_Msk;
 }
 
 /*