diff --git a/tests/lib/sprintf/prj_picolibc.conf b/tests/lib/sprintf/prj_picolibc.conf
index 2cb424d0b1e..205e6bef3c9 100644
--- a/tests/lib/sprintf/prj_picolibc.conf
+++ b/tests/lib/sprintf/prj_picolibc.conf
@@ -2,3 +2,4 @@ CONFIG_ZTEST=y
 CONFIG_ZTEST_NEW_API=y
 CONFIG_PICOLIBC=y
 CONFIG_PICOLIBC_IO_FLOAT=y
+CONFIG_ZTEST_STACK_SIZE=2048
diff --git a/tests/lib/sprintf/prj_picolibc_new.conf b/tests/lib/sprintf/prj_picolibc_new.conf
index 907cf0bc20d..b6d3df39e34 100644
--- a/tests/lib/sprintf/prj_picolibc_new.conf
+++ b/tests/lib/sprintf/prj_picolibc_new.conf
@@ -4,3 +4,4 @@ CONFIG_PICOLIBC=y
 CONFIG_STDOUT_CONSOLE=n
 CONFIG_TEST_USERSPACE=y
 CONFIG_ZTEST_FATAL_HOOK=y
+CONFIG_ZTEST_STACK_SIZE=2048