--- a/mobile/android/base/java/org/mozilla/gecko/widget/DateTimePicker.java
+++ b/mobile/android/base/java/org/mozilla/gecko/widget/DateTimePicker.java
@@ -349,17 +349,17 @@ public class DateTimePicker extends Fram
 
         // Initialize all spinners.
         mDaySpinner = setupSpinner(R.id.day, 1,
                                    mTempDate.get(Calendar.DAY_OF_MONTH));
         mDaySpinner.setFormatter(TWO_DIGIT_FORMATTER);
         mDaySpinnerInput = (EditText) mDaySpinner.getChildAt(1);
 
         mMonthSpinner = setupSpinner(R.id.month, 1,
-                                     mTempDate.get(Calendar.MONTH));
+                                     mTempDate.get(Calendar.MONTH) + 1); // Month is 0-based
         mMonthSpinner.setFormatter(TWO_DIGIT_FORMATTER);
         mMonthSpinner.setDisplayedValues(mShortMonths);
         mMonthSpinnerInput = (EditText) mMonthSpinner.getChildAt(1);
 
         mWeekSpinner = setupSpinner(R.id.week, 1,
                                     mTempDate.get(Calendar.WEEK_OF_YEAR));
         mWeekSpinner.setFormatter(TWO_DIGIT_FORMATTER);
         mWeekSpinnerInput = (EditText) mWeekSpinner.getChildAt(1);