diff --git a/src/license_expression/__init__.py b/src/license_expression/__init__.py
index f856e82..9256ae3 100644
--- a/src/license_expression/__init__.py
+++ b/src/license_expression/__init__.py
@@ -128,7 +128,7 @@ class ExpressionParseError(ParseError, ExpressionError):
 # mapping of lowercase operator strings to an operator object
 OPERATORS = {'and': KW_AND, 'or': KW_OR, 'with': KW_WITH}
 
-_simple_tokenizer = re.compile('''
+_simple_tokenizer = re.compile(r'''
     (?P<symop>[^\s\(\)]+)
      |
     (?P<space>\s+)
diff --git a/src/license_expression/_pyahocorasick.py b/src/license_expression/_pyahocorasick.py
index fefe51f..655de94 100644
--- a/src/license_expression/_pyahocorasick.py
+++ b/src/license_expression/_pyahocorasick.py
@@ -608,7 +608,7 @@ def overlap(self, other):
 
 
 # tokenize to separate text from parens
-_tokenizer = re.compile('''
+_tokenizer = re.compile(r'''
     (?P<text>[^\s\(\)]+)
      |
     (?P<space>\s+)