diff --git a/src/calibre/gui2/tweak_book/__init__.py b/src/calibre/gui2/tweak_book/__init__.py
index 83afbbda4b..a4d041a9ec 100644
--- a/src/calibre/gui2/tweak_book/__init__.py
+++ b/src/calibre/gui2/tweak_book/__init__.py
@@ -57,7 +57,7 @@ d['editor_xml_toolbar'] = ['pretty-current', 'insert-tag']
 d['editor_html_toolbar'] = ['fix-html-current', 'pretty-current', 'insert-image', 'insert-hyperlink', 'insert-tag', 'change-paragraph']
 d['editor_format_toolbar'] = [('format-text-' + x) for x in (
 'bold', 'italic', 'underline', 'strikethrough', 'subscript', 'superscript', 'color', 'background-color')]
-
+d['spell_check_case_sensitive_search'] = False
 del d
 
 ucase_map = {l:string.ascii_uppercase[i] for i, l in enumerate(string.ascii_lowercase)}
diff --git a/src/calibre/gui2/tweak_book/spell.py b/src/calibre/gui2/tweak_book/spell.py
index ddd2169aa0..064fec228c 100644
--- a/src/calibre/gui2/tweak_book/spell.py
+++ b/src/calibre/gui2/tweak_book/spell.py
@@ -31,7 +31,7 @@ from calibre.spell.dictionary import (
     get_dictionary, DictionaryLocale, dprefs, remove_dictionary, rename_dictionary)
 from calibre.spell.import_from import import_from_oxt
 from calibre.utils.localization import calibre_langcode_to_name, get_language, get_lang, canonicalize_lang
-from calibre.utils.icu import sort_key, primary_sort_key, primary_contains
+from calibre.utils.icu import sort_key, primary_sort_key, primary_contains, contains
 
 LANG = 0
 COUNTRY = 1
@@ -693,7 +693,8 @@ class WordsModel(QAbstractTableModel):
     def filter_item(self, x):
         if self.show_only_misspelt and self.spell_map[x]:
             return False
-        if self.filter_expression is not None and not primary_contains(self.filter_expression, x[0]):
+        func = contains if tprefs['spell_check_case_sensitive_search'] else primary_contains
+        if self.filter_expression is not None and not func(self.filter_expression, x[0]):
             return False
         return True
 
@@ -986,10 +987,15 @@ class SpellCheck(Dialog):
         om.stateChanged.connect(self.update_show_only_misspelt)
         self.case_sensitive_sort = cs = QCheckBox(_('Case &sensitive sort'))
         cs.setChecked(tprefs['spell_check_case_sensitive_sort'])
+        cs.setToolTip(_('When sorting the list of words, be case sensitive'))
         cs.stateChanged.connect(self.sort_type_changed)
+        self.case_sensitive_search = cs2 = QCheckBox(_('Case sensitive sea&rch'))
+        cs2.setToolTip(_('When filtering the list of words, be case sensitive'))
+        cs2.setChecked(tprefs['spell_check_case_sensitive_search'])
+        cs2.stateChanged.connect(self.search_type_changed)
         self.hb = h = QHBoxLayout()
         self.summary = s = QLabel('')
-        self.main.l.addLayout(h), h.addWidget(s), h.addWidget(om), h.addWidget(cs), h.addStretch(1)
+        self.main.l.addLayout(h), h.addWidget(s), h.addWidget(om), h.addWidget(cs), h.addWidget(cs2), h.addStretch(1)
 
     def keyPressEvent(self, ev):
         if ev.key() in (Qt.Key_Enter, Qt.Key_Return):
@@ -1004,6 +1010,11 @@ class SpellCheck(Dialog):
                 hh = self.words_view.horizontalHeader()
                 self.words_view.sortByColumn(hh.sortIndicatorSection(), hh.sortIndicatorOrder())
 
+    def search_type_changed(self):
+        tprefs['spell_check_case_sensitive_search'] = bool(self.case_sensitive_search.isChecked())
+        if unicode(self.filter_text.text()).strip():
+            self.do_filter()
+
     def show_next_occurrence(self):
         self.word_activated(self.words_view.currentIndex())