diff --git a/bigtext.py b/bigtext.py
index 0b28301..cec0c44 100644
--- a/bigtext.py
+++ b/bigtext.py
@@ -117,6 +117,8 @@ class InnerBigText(QWidget):
         self.update_font_metrics(QPainter(self))
         self.lines = []
         self.selection_highlight = HighlightSelection()
+        self._last_double_click_time = 0
+        self._last_double_click_line_number = -1
 
     def keyPressEvent(self, e: QKeyEvent) -> None:
 
@@ -184,6 +186,16 @@ class InnerBigText(QWidget):
             self.update()
             return
 
+        if e.buttons() == Qt.MouseButton.LeftButton and (time.time() - self._last_double_click_time) < 0.5:
+            # triple click: select line
+            line_number = self.y_pos_to_line(e.pos().y())
+            if line_number == self._last_double_click_line_number and line_number < len(self.lines):
+                line = self.lines[line_number]
+                self.selection_highlight.set_start(line.byte_offset())
+                self.selection_highlight.set_end_byte(line.byte_end())
+                self.update()
+                return
+
         if e.buttons() == Qt.MouseButton.LeftButton and e.modifiers() == Qt.KeyboardModifier.NoModifier:
             offset = self.to_byte_offset(e)
             self.selection_highlight.set_start(offset)
@@ -192,6 +204,9 @@ class InnerBigText(QWidget):
 
     def mouseDoubleClickEvent(self, e: QtGui.QMouseEvent) -> None:
         if e.buttons() == Qt.MouseButton.LeftButton:
+            self._last_double_click_time = time.time()
+            self._last_double_click_line_number = self.y_pos_to_line(e.pos().y())
+
             offset = self.to_byte_offset(e)
             (_word, start_byte, end_byte) = self.model.read_word_at(offset)
             if start_byte >= 0 and end_byte >= 0: