diff --git a/var/spack/repos/builtin/packages/libvterm/package.py b/var/spack/repos/builtin/packages/libvterm/package.py
index aef6d23d27..edec3b1ae8 100644
--- a/var/spack/repos/builtin/packages/libvterm/package.py
+++ b/var/spack/repos/builtin/packages/libvterm/package.py
@@ -13,6 +13,8 @@ class Libvterm(Package):
 
     version('681', '7a4325a7350b7092245c04e8ee185ac3')
 
+    depends_on('libtool', type='build')
+
     def install(self, spec, prefix):
         make()
         make("install", "PREFIX=" + prefix)
diff --git a/var/spack/repos/builtin/packages/unibilium/package.py b/var/spack/repos/builtin/packages/unibilium/package.py
index dd1d1514ed..66579b0bb2 100644
--- a/var/spack/repos/builtin/packages/unibilium/package.py
+++ b/var/spack/repos/builtin/packages/unibilium/package.py
@@ -13,6 +13,8 @@ class Unibilium(Package):
 
     version('1.2.0', '9b1c97839a880a373da6c097443b43c4')
 
+    depends_on('libtool', type='build')
+
     def install(self, spec, prefix):
         make("PREFIX=" + prefix)
         make("install", "PREFIX=" + prefix)