diff --git a/chalice/compat.py b/chalice/compat.py
index eb2e07358..29f3ea751 100644
--- a/chalice/compat.py
+++ b/chalice/compat.py
@@ -11,10 +11,13 @@ def pip_import_string():
     # type: () -> str
     import pip
     pip_major_version = pip.__version__.split('.')[0]
-    if pip_major_version == '10':
-        return 'from pip._internal import main'
-    else:
+    # Pip moved its internals to an _internal module in version 10.
+    # In order to be compatible with version 9 which has it at at the
+    # top level we need to figure out the correct import path here.
+    if pip_major_version == '9':
         return 'from pip import main'
+    else:
+        return 'from pip._internal import main'
 
 
 if os.name == 'nt':
diff --git a/setup.py b/setup.py
index 2ebacce05..535d52a22 100644
--- a/setup.py
+++ b/setup.py
@@ -11,7 +11,7 @@
     'botocore>=1.10.48,<2.0.0',
     'typing==3.6.4',
     'six>=1.10.0,<2.0.0',
-    'pip>=9,<11',
+    'pip>=9,<=18',
     'attrs==17.4.0',
     'enum-compat>=0.0.2',
     'jmespath>=0.9.3,<1.0.0',