diff --git a/Options.hs b/Options.hs
index 544ed10f9..1fc4fb88a 100644
--- a/Options.hs
+++ b/Options.hs
@@ -78,6 +78,7 @@ options = [
 -- ,Option ['s'] ["subtotal"]     (NoArg  SubTotal)      "balance report: show subaccounts"
  ,Option ['W'] ["weekly"]       (NoArg  WeeklyOpt)     "register report: show weekly summary"
  ,Option ['M'] ["monthly"]      (NoArg  MonthlyOpt)    "register report: show monthly summary"
+ ,Option ['Q'] ["quarterly"]    (NoArg  QuarterlyOpt)  "register report: show quarterly summary"
  ,Option ['Y'] ["yearly"]       (NoArg  YearlyOpt)     "register report: show yearly summary"
  ,Option ['h'] ["help"] (NoArg  Help)                  "show this help"
  ,Option ['V'] ["version"]      (NoArg  Version)       "show version information"
@@ -103,6 +104,7 @@ data Opt =
     SubTotal |
     WeeklyOpt |
     MonthlyOpt |
+    QuarterlyOpt |
     YearlyOpt |
     Help |
     Verbose |
@@ -178,10 +180,11 @@ intervalFromOpts opts
     | otherwise = case last otheropts of
                     WeeklyOpt  -> Weekly
                     MonthlyOpt -> Monthly
+                    QuarterlyOpt -> Quarterly
                     YearlyOpt  -> Yearly
     where
       popts = optValuesForConstructor Period opts
-      otheropts = filter (`elem` [WeeklyOpt,MonthlyOpt,YearlyOpt]) opts 
+      otheropts = filter (`elem` [WeeklyOpt,MonthlyOpt,QuarterlyOpt,YearlyOpt]) opts
       -- doesn't affect the interval, but parsePeriodExpr needs something
       refdate = parsedate "0001/01/01"
 
diff --git a/Tests.hs b/Tests.hs
index fde0486c0..1b125c79a 100644
--- a/Tests.hs
+++ b/Tests.hs
@@ -490,9 +490,11 @@ tests = [
     [] `gives` NoInterval
     [WeeklyOpt] `gives` Weekly
     [MonthlyOpt] `gives` Monthly
+    [QuarterlyOpt] `gives` Quarterly
     [YearlyOpt] `gives` Yearly
     [Period "weekly"] `gives` Weekly
     [Period "monthly"] `gives` Monthly
+    [Period "quarterly"] `gives` Quarterly
     [WeeklyOpt, Period "yearly"] `gives` Yearly
 
   ,"isAccountNamePrefixOf" ~: do
@@ -731,6 +733,7 @@ tests = [
     "2007" `gives` []
     "june" `gives` ["2008/06/01","2008/06/02","2008/06/03"]
     "monthly" `gives` ["2008/01/01","2008/06/01","2008/12/01"]
+    "quarterly" `gives` ["2008/01/01","2008/04/01","2008/10/01"]
     showRegisterReport [Period "yearly"] [] l `is` unlines
      ["2008/01/01 - 2008/12/31         assets:bank:saving               $1           $1"
      ,"                                assets:cash                     $-2          $-1"