diff --git a/mdx_attr_cols.py b/mdx_attr_cols.py
new file mode 100644
index 0000000..8618d6d
--- /dev/null
+++ b/mdx_attr_cols.py
@@ -0,0 +1,89 @@
+""" Bootstrap 3 grid extension fo Python Markdown
+"""
+
+from xml.etree import ElementTree as etree
+
+from markdown import Extension
+from markdown.treeprocessors import Treeprocessor
+
+
+class AttrColTreeProcessor(Treeprocessor):
+    """ The attr_cols element tree processor. """
+
+    CONF_DEFAULTS = {
+        'columns': 12,
+        'attr': 'cols',
+        'tags': ['section'],
+    }
+
+    def __init__(self, md, conf):
+        super(AttrColTreeProcessor, self).__init__(md)
+        conf_vars = self.CONF_DEFAULTS.copy()
+        conf_vars.update(conf or {})
+        self.columns = int(conf_vars.get('columns'))
+        self.attr = str(conf_vars.get('attr'))
+        self.tags = set(conf_vars.get('tags'))
+
+    def create_rows(self, node):
+        row, row_cols = None, 0
+        for i, child in enumerate(list(node)):
+            if child.tag.lower() not in self.tags:
+                continue
+
+            if self.attr not in child.attrib:
+                if row is None:
+                    # if there currently isn't a row, search sub-sections
+                    self.create_rows(child)
+                else:
+                    row, row_cols = None, 0
+                continue
+            cols = int(child.attrib[self.attr])
+            del child.attrib[self.attr]
+
+            if row is None:
+                row = etree.Element("div", {"class": "row"})
+                node.insert(i, row)
+
+            col = etree.SubElement(row, "div", {
+                "class": "col-md-%d" % (cols,),
+            })
+            row_cols += cols
+
+            col.append(child)
+            node.remove(child)
+
+            if row_cols >= self.columns:
+                row, row_cols = None, 0
+
+    def run(self, root):
+        self.create_rows(root)
+        return root
+
+
+class AttrColExtension(Extension):
+    """ The attr_cols markdown extension. """
+
+    REQUIRED_EXTENSIONS = ('attr_list', 'mdx_outline')
+    REQUIRED_EXTENSION_INTERNAL_NAMES = ('attr_list', 'outline')
+
+    def __init__(self, configs):
+        self.conf = configs
+
+    def extendMarkdown(self, md, md_globals=None):
+        """Initializes markdown extension components."""
+        if any(
+                x not in md.treeprocessors
+                for x in self.REQUIRED_EXTENSION_INTERNAL_NAMES):
+            raise RuntimeError(
+                "The attr_cols markdown extension depends the following"
+                " extensions which must preceded it in the extension"
+                " list: %s" % ", ".join(self.REQUIRED_EXTENSIONS))
+        processor = AttrColTreeProcessor(md, self.conf)
+        md.treeprocessors.register(
+            processor, 'attr_cols',
+            5)  # 5 is the lowest priority
+
+
+def makeExtension(**kwargs):
+    """ Initialize the attr_cols extension. """
+    return AttrColExtension(configs=kwargs)