diff --git a/spec/workspace-spec.coffee b/spec/workspace-spec.coffee
index 61da334bb..9b8ce4d50 100644
--- a/spec/workspace-spec.coffee
+++ b/spec/workspace-spec.coffee
@@ -428,7 +428,7 @@ describe "Workspace", ->
 
   describe "::resetFontSize()", ->
     it "resets the font size to the window's starting font size", ->
-      originalFontSize = 6
+      originalFontSize = atom.config.get('editor.fontSize')
 
       atom.config.set('editor.fontSize', originalFontSize)
       workspace.increaseFontSize()
@@ -441,12 +441,22 @@ describe "Workspace", ->
       expect(atom.config.get('editor.fontSize')).toBe originalFontSize
 
     it "does nothing if the font size has not been changed", ->
-      originalFontSize = 6
+      originalFontSize = atom.config.get('editor.fontSize')
 
       atom.config.set('editor.fontSize', originalFontSize)
       workspace.resetFontSize()
       expect(atom.config.get('editor.fontSize')).toBe originalFontSize
 
+    it "resets the font size when the editor's font size changes", ->
+      originalFontSize = atom.config.get('editor.fontSize')
+
+      atom.config.set('editor.fontSize', originalFontSize + 1)
+      workspace.resetFontSize()
+      expect(atom.config.get('editor.fontSize')).toBe originalFontSize
+      atom.config.set('editor.fontSize', originalFontSize - 1)
+      workspace.resetFontSize()
+      expect(atom.config.get('editor.fontSize')).toBe originalFontSize
+
   describe "::openLicense()", ->
     it "opens the license as plain-text in a buffer", ->
       waitsForPromise -> workspace.openLicense()
diff --git a/src/workspace.coffee b/src/workspace.coffee
index 2f70e4316..07040463b 100644
--- a/src/workspace.coffee
+++ b/src/workspace.coffee
@@ -75,6 +75,8 @@ class Workspace extends Model
     atom.views.addViewProvider Panel, (model) ->
       new PanelElement().initialize(model)
 
+    @subscribeToFontSize()
+
   # Called by the Serializable mixin during deserialization
   deserializeParams: (params) ->
     for packageName in params.packagesWithActiveGrammars ? []
@@ -612,12 +614,10 @@ class Workspace extends Model
 
   # Increase the editor font size by 1px.
   increaseFontSize: ->
-    @originalFontSize ?= atom.config.get("editor.fontSize")
     atom.config.set("editor.fontSize", atom.config.get("editor.fontSize") + 1)
 
   # Decrease the editor font size by 1px.
   decreaseFontSize: ->
-    @originalFontSize ?= atom.config.get("editor.fontSize")
     fontSize = atom.config.get("editor.fontSize")
     atom.config.set("editor.fontSize", fontSize - 1) if fontSize > 1
 
@@ -626,6 +626,10 @@ class Workspace extends Model
     if @originalFontSize
       atom.config.set("editor.fontSize", @originalFontSize)
 
+  subscribeToFontSize: ->
+    atom.config.onDidChange 'editor.fontSize', ({newValue, oldValue}) =>
+      @originalFontSize ?= oldValue
+
   # Removes the item's uri from the list of potential items to reopen.
   itemOpened: (item) ->
     if typeof item.getURI is 'function'