diff --git a/Makefile b/Makefile
index d64dd08f..20ffb6a0 100644
--- a/Makefile
+++ b/Makefile
@@ -82,6 +82,8 @@ help:
 	@echo ""
 	@echo "  "make build_name=mytest module=dsound module" - Build only the dsound module"
 	@echo "      in the \"mytest\" build directory and place it into vagrant_share/dsound/."
+	@echo ""
+	@echo "Running out of disk space in the VM? See resize-vagrant-disk.sh"
 
 vagrant:
 	vagrant up
diff --git a/resize-vagrant-disk.sh b/resize-vagrant-disk.sh
new file mode 100755
index 00000000..0ffe1ecd
--- /dev/null
+++ b/resize-vagrant-disk.sh
@@ -0,0 +1,100 @@
+#!/bin/bash
+
+#this script resizes the build VM disk image.  the generic/debian9 box that we
+#use only ships a 32G disk, which is only just large enough to hold the Steam
+#runtime, two Wine build trees, and final Proton dist/ folder.
+
+set -e
+
+NOTE_STYLE="\e[31m\e[1m"
+RESET_STYLE="\e[0m"
+
+NEW_LIBVIRT_DISK_SIZE=128G
+
+function note {
+    echo -e "$NOTE_STYLE""$1""$RESET_STYLE"
+}
+
+function usage {
+    note "To automatically resize a libvirt disk to $NEW_LIBVIRT_DISK_SIZE:"
+    echo ""
+    echo -e "\t$0 --libvirt-disk <libvirt disk path>"
+    echo ""
+    note "You may find the disk path with \"virsh vol-list default\"."
+    echo ""
+    note "Or, if you've already manually resized the disk (e.g. VirtualBox users):"
+    echo ""
+    echo -e "\t$0 --resize-vm-partition"
+    exit 1
+}
+
+#to be run from within the VM
+if [ "$1" == "--fdisk" ]; then
+    sudo sfdisk -d /dev/sda > /tmp/sda.sfdisk
+
+    #remove start and size params from sda3 line, sfdisk will automatically use the rest of the disk
+    sed -e "s/^.dev.sda3.*$/\/dev\/sda3 : type=83/" < /tmp/sda.sfdisk | sudo sfdisk --force /dev/sda
+
+    exit
+
+#to be run from within the VM
+elif [ "$1" == "--resize2fs" ]; then
+    #resize2fs automatically uses the whole partition
+    sudo resize2fs /dev/sda3
+
+    exit
+
+#libvirt disk image to resize
+elif [ "$1" == "--libvirt-disk" ]; then
+    if [ -z "$2" ]; then
+        note "You must give a disk path to --libvirt-disk"
+        echo ""
+        usage
+        exit 1
+    fi
+    LIBVIRT_DISK_PATH="$2"
+
+    note "Going to resize disk $LIBVIRT_DISK_PATH"
+    note "Shutting down VM"
+    vagrant halt
+
+    note "Resizing the VM disk image"
+    virsh vol-resize "$LIBVIRT_DISK_PATH" "$NEW_LIBVIRT_DISK_SIZE" --pool default
+
+#just resize the partition in the VM
+elif [ "$1" == "--resize-vm-partition" ]; then
+    : #noop
+
+else
+    if [ -n "$1" -a "$1" != "--help" -a "$1" != "-h" ]; then
+        note "Unknown argument: $1"
+        exit 1
+    fi
+    usage
+    exit 1
+fi
+
+note "Starting the VM"
+vagrant up
+vagrant rsync
+
+note "Repartitioning the disk"
+vagrant ssh -c "/home/vagrant/proton/resize-vagrant-disk.sh --fdisk"
+
+note "Restarting the VM"
+#seems to be necessary for resize2fs to pick up on the new partition size
+#maybe there's a way to do that without rebooting?
+vagrant halt
+vagrant up
+
+note "Resizing the filesystem"
+vagrant ssh -c "/home/vagrant/proton/resize-vagrant-disk.sh --resize2fs"
+
+note "Here's the output from \"df -h /dev/sda3\":"
+vagrant ssh -c "df -h /dev/sda3"
+
+note "Shutting down the VM"
+#just to be sure everything is in a clean state
+vagrant halt
+
+note "Done!"