diff --git a/ui/bookmarklist.cpp b/ui/bookmarklist.cpp
--- a/ui/bookmarklist.cpp
+++ b/ui/bookmarklist.cpp
@@ -124,6 +124,7 @@
 
     m_searchLine = new KTreeWidgetSearchLine( this );
     mainlay->addWidget( m_searchLine );
+    m_searchLine->setPlaceholderText(i18n( "Search..." ));
 
     m_tree = new QTreeWidget( this );
     mainlay->addWidget( m_tree );
diff --git a/ui/searchwidget.cpp b/ui/searchwidget.cpp
--- a/ui/searchwidget.cpp
+++ b/ui/searchwidget.cpp
@@ -37,6 +37,7 @@
     // 2. text line
     m_lineEdit = new SearchLineEdit( this, document );
     m_lineEdit->setClearButtonEnabled( true );
+    m_lineEdit->setPlaceholderText(i18n( "Search..." ));
     m_lineEdit->setToolTip(i18n( "Enter at least 3 letters to filter pages" ));
     m_lineEdit->setSearchCaseSensitivity( Qt::CaseInsensitive );
     m_lineEdit->setSearchMinimumLength( 3 );
diff --git a/ui/side_reviews.cpp b/ui/side_reviews.cpp
--- a/ui/side_reviews.cpp
+++ b/ui/side_reviews.cpp
@@ -117,6 +117,7 @@
     m_view->setModel( m_authorProxy );
 
     m_searchLine = new KTreeViewSearchLine( this, m_view );
+    m_searchLine->setPlaceholderText(i18n( "Search..." ));
     m_searchLine->setCaseSensitivity( Okular::Settings::self()->reviewsSearchCaseSensitive() ? Qt::CaseSensitive : Qt::CaseInsensitive );
     m_searchLine->setRegularExpression( Okular::Settings::self()->reviewsSearchRegularExpression() );
     connect(m_searchLine, &KTreeViewSearchLine::searchOptionsChanged, this, &Reviews::saveSearchOptions);
diff --git a/ui/toc.cpp b/ui/toc.cpp
--- a/ui/toc.cpp
+++ b/ui/toc.cpp
@@ -17,6 +17,7 @@
 #include <QContextMenuEvent>
 
 #include <klineedit.h>
+#include <KLocalizedString>
 
 // local includes
 #include "ktreeviewsearchline.h"
@@ -34,6 +35,7 @@
 
     m_searchLine = new KTreeViewSearchLine( this );
     mainlay->addWidget( m_searchLine );
+    m_searchLine->setPlaceholderText(i18n( "Search..." ));
     m_searchLine->setCaseSensitivity( Okular::Settings::self()->contentsSearchCaseSensitive() ? Qt::CaseSensitive : Qt::CaseInsensitive );
     m_searchLine->setRegularExpression( Okular::Settings::self()->contentsSearchRegularExpression() );
     connect(m_searchLine, &KTreeViewSearchLine::searchOptionsChanged, this, &TOC::saveSearchOptions);