diff --git a/spacy/lang/char_classes.py b/spacy/lang/char_classes.py
index bec685646..f4b21b233 100644
--- a/spacy/lang/char_classes.py
+++ b/spacy/lang/char_classes.py
@@ -27,6 +27,7 @@ ALPHA_UPPER = merge_char_classes(_upper + _uncased)
 
 _units = ('km km² km³ m m² m³ dm dm² dm³ cm cm² cm³ mm mm² mm³ ha µm nm yd in ft '
           'kg g mg µg t lb oz m/s km/h kmh mph hPa Pa mbar mb MB kb KB gb GB tb '
+          'kHz MHz GHz '
           'TB T G M K')
 _currency = r'\$ £ € ¥ ฿ US\$ C\$ A\$'
 _punct = r'… , : ; \! \? ¿ ¡ \( \) \[ \] \{ \} < > _ # \* &'