diff --git a/meta-python/recipes-core/images/meta-python-image-ptest.bb b/meta-python/recipes-core/images/meta-python-image-ptest.bb
index 9c542855a2..002bd7a39e 100644
--- a/meta-python/recipes-core/images/meta-python-image-ptest.bb
+++ b/meta-python/recipes-core/images/meta-python-image-ptest.bb
@@ -27,6 +27,10 @@ IMAGE_ROOTFS_EXTRA_SPACE = "324288"
 QB_MEM = "-m 1024"
 # If a particular ptest needs more memory, it can be customized:
 #QB_MEM:virtclass-mcextend-<pn> = "-m 4096"
+# python3-scrypt ptests run into OOMs on RISCV64 qemu
+QB_MEM:virtclass-mcextend-python3-scrypt = "-m 2048"
+QB_MEM:virtclass-mcextend-python3-fastjsonschema = "-m 2048"
+QB_MEM:virtclass-mcextend-python3-pillow = "-m 2048"
 
 TEST_SUITES = "ping ssh parselogs ptest"