diff --git a/app/assets/javascripts/zen_mode.js.coffee b/app/assets/javascripts/zen_mode.js.coffee
index 8a0564a909815a0b696c6828d8275503755d80e7..a1462cf3cae65822be84d0d3df21117bc0f610b1 100644
--- a/app/assets/javascripts/zen_mode.js.coffee
+++ b/app/assets/javascripts/zen_mode.js.coffee
@@ -38,6 +38,8 @@ class @ZenMode
     @active_checkbox = $(checkbox)
     @active_checkbox.prop('checked', true)
     @active_zen_area = @active_checkbox.parent().find('textarea')
+    # Prevent a user-resized textarea from persisting to fullscreen
+    @active_zen_area.removeAttr('style')
     @active_zen_area.focus()
 
   exitZenMode: =>
diff --git a/spec/javascripts/zen_mode_spec.js.coffee b/spec/javascripts/zen_mode_spec.js.coffee
index 1f4ea58ad484c0fa98e5ca00635b59cc3bef7f2e..4cb3836755f881abd9d4f03928a7b63e4326520d 100644
--- a/spec/javascripts/zen_mode_spec.js.coffee
+++ b/spec/javascripts/zen_mode_spec.js.coffee
@@ -29,6 +29,11 @@ describe 'ZenMode', ->
       enterZen()
       expect(Mousetrap.pause).toHaveBeenCalled()
 
+    it 'removes textarea styling', ->
+      $('textarea').attr('style', 'height: 400px')
+      enterZen()
+      expect('textarea').not.toHaveAttr('style')
+
   describe 'in use', ->
     beforeEach ->
       enterZen()