diff --git a/mwparserfromhell/parser/tokenizer.py b/mwparserfromhell/parser/tokenizer.py
index f09adc8..b899e75 100644
--- a/mwparserfromhell/parser/tokenizer.py
+++ b/mwparserfromhell/parser/tokenizer.py
@@ -63,7 +63,7 @@ class Tokenizer(object):
     START = object()
     END = object()
     MARKERS = ["{", "}", "[", "]", "<", ">", "|", "=", "&", "'", "#", "*", ";",
-               ":", "/", "-", "\n", START, END]
+               ":", "/", "-", "!", "\n", START, END]
     MAX_DEPTH = 40
     MAX_CYCLES = 100000
     regex = re.compile(r"([{}\[\]<>|=&'#*;:/\\\"\-!\n])", flags=re.IGNORECASE)
diff --git a/tests/tokenizer/tables.mwtest b/tests/tokenizer/tables.mwtest
index e7eb40c..1087381 100644
--- a/tests/tokenizer/tables.mwtest
+++ b/tests/tokenizer/tables.mwtest
@@ -61,6 +61,20 @@ output: [TagOpenOpen(wiki_markup="{|"), Text(text="table"), TagCloseOpen(), Text
 
 ---
 
+name:   table_header_simple
+label:  Simple header cell.
+input:  "{|\n ! foo \n|}"
+output: [TagOpenOpen(wiki_markup="{|"), Text(text="table"), TagCloseOpen(), Text(text="\n "), TagOpenOpen(wiki_markup="!"), Text(text="th"), TagCloseSelfclose(), Text(text=" foo \n"), TagOpenClose(), Text(text="table"), TagCloseClose()]
+
+---
+
+name:   table_header_inline
+label:  Multiple inline header cells.
+input:  "{|\n ! foo || bar !! test \n|}"
+output: [TagOpenOpen(wiki_markup="{|"), Text(text="table"), TagCloseOpen(), Text(text="\n "), TagOpenOpen(wiki_markup="!"), Text(text="th"), TagCloseSelfclose(), Text(text=" foo "), TagOpenOpen(wiki_markup="||"), Text(text="th"), TagCloseSelfclose(), Text(text=" bar "),TagOpenOpen(wiki_markup="!!"), Text(text="th"), TagCloseSelfclose(), Text(text=" test \n"), TagOpenClose(), Text(text="table"), TagCloseClose()]
+
+---
+
 name:   nowiki_inside_table
 label:  Nowiki handles pipe characters in tables.
 input:  "{|\n | foo <nowiki>| |- {| |} || ! !!</nowiki> bar \n|}"