diff --git a/tests/kernel/mem_protect/userspace/src/main.c b/tests/kernel/mem_protect/userspace/src/main.c
index 57ed77a5b34..1ebe0aa3655 100644
--- a/tests/kernel/mem_protect/userspace/src/main.c
+++ b/tests/kernel/mem_protect/userspace/src/main.c
@@ -1046,9 +1046,9 @@ void kernel_only_thread_entry(void *p1, void *p2, void *p3)
 }
 
 #ifdef CONFIG_MMU
-#define KERNEL_ONLY_THREAD_STACK_SIZE (ROUND_UP(512, CONFIG_MMU_PAGE_SIZE))
+#define KERNEL_ONLY_THREAD_STACK_SIZE (ROUND_UP(1024, CONFIG_MMU_PAGE_SIZE))
 #else
-#define KERNEL_ONLY_THREAD_STACK_SIZE (512)
+#define KERNEL_ONLY_THREAD_STACK_SIZE (1024)
 #endif
 
 static K_KERNEL_THREAD_DEFINE(kernel_only_thread,
diff --git a/tests/lib/sprintf/prj.conf b/tests/lib/sprintf/prj.conf
index 738afb095a3..34bba7f359e 100644
--- a/tests/lib/sprintf/prj.conf
+++ b/tests/lib/sprintf/prj.conf
@@ -4,3 +4,4 @@ CONFIG_FPU=y
 CONFIG_TEST_USERSPACE=y
 CONFIG_ZTEST_FATAL_HOOK=y
 CONFIG_PICOLIBC_IO_FLOAT=y
+CONFIG_ZTEST_STACK_SIZE=2048
diff --git a/tests/lib/sprintf/prj_new.conf b/tests/lib/sprintf/prj_new.conf
index 0934c7755eb..eee90586e22 100644
--- a/tests/lib/sprintf/prj_new.conf
+++ b/tests/lib/sprintf/prj_new.conf
@@ -4,3 +4,4 @@ CONFIG_ZTEST_NEW_API=y
 CONFIG_FPU=y
 CONFIG_TEST_USERSPACE=y
 CONFIG_ZTEST_FATAL_HOOK=y
+CONFIG_ZTEST_STACK_SIZE=2048