diff --git a/README.md b/README.md
index 2713ef2..1683ea6 100644
--- a/README.md
+++ b/README.md
@@ -35,7 +35,7 @@ with pip: `pip install treesource`.
 ## Usage
 Execute the python module from the root folder: `python -m treesource`
 ```
-usage: python -m treesource [-h] [-u] [-a] [-r PATH] [-f FORMAT]
+usage: python -m treesource [-h] [-u] [-a] [-r PATH] [-f FORMAT] [-i ENCODING]
 
 Source file-trees generator.
 
@@ -46,6 +46,8 @@ optional arguments:
   -r PATH, --root PATH  the root directory of the tree
   -f FORMAT, --format FORMAT
                         the rendering format [txt|md|ascii]
+  -i ENCODING, --input_encoding ENCODING
+                        the encoding that shall be assumed for the treesource.txt files
 ```
 
 ## Output formats
diff --git a/treesource/__main__.py b/treesource/__main__.py
index 872e2e3..7995d36 100644
--- a/treesource/__main__.py
+++ b/treesource/__main__.py
@@ -21,10 +21,12 @@
 
     parser.add_argument('-f', '--format', metavar='FORMAT', type=str,
                         default='txt', help='the rendering format [txt|md|ascii]')
+    parser.add_argument('-i', '--input_encoding', type=str,
+                        default=None, help='the encoding assumed for the treesource.txt e.g. utf-8')
     args = parser.parse_args()
 
     # generate the tree
-    tree = generate_tree(args.root, keep_undocumented=args.show_all)
+    tree = generate_tree(args.root, keep_undocumented=args.show_all, input_encoding=args.input_encoding)
 
     # render the tree
     if args.format.upper() in ['MD', 'MARKDOWN']:
diff --git a/treesource/scan.py b/treesource/scan.py
index 7e920ed..dac6c94 100644
--- a/treesource/scan.py
+++ b/treesource/scan.py
@@ -3,13 +3,13 @@
 from anytree import AnyNode, PostOrderIter
 
 
-def get_doc_string(path, first_lines=30):
+def get_doc_string(path, first_lines=30, input_encoding=None):
     """look for the doctree docstring in the first lines of the file in path"""
 
     docstring = None
 
     try:
-        f = open(path, 'r')
+        f = open(path, 'r', encoding=input_encoding)
     except Exception:
         return None
 
@@ -81,7 +81,7 @@ def walk2tree(walk_lsit, prune_undocumented):
     return root
 
 
-def generate_tree(startpath, keep_undocumented=False):
+def generate_tree(startpath, keep_undocumented=False, input_encoding=None):
     """Generate a file-tree object from the current working directory.
 
     keep_undocumented: keep undocumented files and directories in the tree
@@ -102,7 +102,7 @@ def generate_tree(startpath, keep_undocumented=False):
         documented_files = []
         for filename in files:
             # look for the docstring in the file
-            docstring = get_doc_string(os.path.join(root, filename))
+            docstring = get_doc_string(os.path.join(root, filename),input_encoding=input_encoding)
             # speed up by not inserting undocumented diles
             if keep_undocumented or (docstring is not None):
                 documented_files.append(dict(
@@ -114,7 +114,7 @@ def generate_tree(startpath, keep_undocumented=False):
         dirdoc = None
         docfile = os.path.join(root, 'treesource.txt')
         if os.path.exists(docfile):
-            with open(docfile, 'r') as f:
+            with open(docfile, 'r', encoding=input_encoding) as f:
                 dirdoc = f.readline()
 
         walked.append(dict(