diff --git a/lib/oga/css/lexer.rl b/lib/oga/css/lexer.rl
index 3ef0a45..75e81ac 100644
--- a/lib/oga/css/lexer.rl
+++ b/lib/oga/css/lexer.rl
@@ -23,7 +23,7 @@ module Oga
 
       # @param [String] data The data to lex.
       def initialize(data)
-        @data = data
+        @data = data.strip
       end
 
       # Gathers all the tokens for the input and returns them as an Array.
diff --git a/spec/oga/css/lexer_spec.rb b/spec/oga/css/lexer_spec.rb
new file mode 100644
index 0000000..d00e347
--- /dev/null
+++ b/spec/oga/css/lexer_spec.rb
@@ -0,0 +1,7 @@
+require 'spec_helper'
+
+describe Oga::CSS::Lexer do
+  it 'ignores leading and trailing whitespace' do
+    expect(lex_css(' foo ')).to eq([[:T_IDENT, 'foo']])
+  end
+end