diff --git a/src/components/calendar/README.md b/src/components/calendar/README.md
index 3efb92ff386..31c15a3d176 100644
--- a/src/components/calendar/README.md
+++ b/src/components/calendar/README.md
@@ -282,6 +282,23 @@ Notes:
 - `year`, `month` and `day` will always be shown. If you need to leave out a value, set the property
   to `undefined`, although this is highly discouraged for accessibility reasons
 
+### Weekday name header format
+
+<span class="badge badge-info small">2.12.0+</span>
+
+The calendar weekday name header format defaults to `'short'`, which is typically a three-character
+abbreviation of the weekday, although some [locales](#internationalization) may override this. The
+format can be controlled via the prop `weekday-header-format` and accepts one of three values:
+
+- `'long'` the full weekday name (e.g. <samp>Tuesday</samp>). Handy when using a full width
+  calendar. Avoid using with the default calendar width.
+- `'short'` typically is a 2 or 3 letter abbreviation of the weekday name, depending on the selected
+  locale (e.g. "Tue").
+- `'narrow'` is typically a single character abbreviation (e.g., <samp>T</samp>). Two weekdays may
+  have the same narrow style for some locales (e.g. Tuesday and Thursday's narrow style are both
+  <samp>T</samp>). This can be handy for those locales that do not support the `'short'` format,
+  such as locales `'ar'` and `'fa'`.
+
 ### Hiding the top selected date header
 
 By default, the current selected date will be displayed at the top of the calendar component,
@@ -592,6 +609,7 @@ the same locale as requested, depending on the supported locales of `Intl`).
             labelHelp: 'Mit den Pfeiltasten durch den Kalender navigieren'
           },
           'ar-EG': {
+            weekdayHeaderFormat: 'narrow',
             labelPrevDecade: 'العقد السابق',
             labelPrevYear: 'العام السابق',
             labelPrevMonth: 'الشهر السابق',
@@ -607,6 +625,7 @@ the same locale as requested, depending on the supported locales of `Intl`).
             labelHelp: 'استخدم مفاتيح المؤشر للتنقل في التواريخ'
           },
           zh: {
+            weekdayHeaderFormat: 'narrow',
             labelPrevDecade: '过去十年',
             labelPrevYear: '上一年',
             labelPrevMonth: '上个月',
diff --git a/src/components/calendar/calendar.js b/src/components/calendar/calendar.js
index b1a9e5e42ef..5392a5a8d24 100644
--- a/src/components/calendar/calendar.js
+++ b/src/components/calendar/calendar.js
@@ -42,6 +42,14 @@ const NAME = 'BCalendar'
 // Key Codes
 const { UP, DOWN, LEFT, RIGHT, PAGEUP, PAGEDOWN, HOME, END, ENTER, SPACE } = KeyCodes
 
+// Common calendar option value strings
+export const STR_GREGORY = 'gregory'
+export const STR_NUMERIC = 'numeric'
+export const STR_2_DIGIT = '2-digit'
+export const STR_LONG = 'long'
+export const STR_SHORT = 'short'
+export const STR_NARROW = 'narrow'
+
 // --- BCalendar component ---
 
 // @vue/component
@@ -224,13 +232,25 @@ export const BCalendar = Vue.extend({
     },
     dateFormatOptions: {
       // `Intl.DateTimeFormat` object
+      // Note: This value is *not* to be placed in the global config
       type: Object,
       default: () => ({
-        year: 'numeric',
-        month: 'long',
-        day: 'numeric',
-        weekday: 'long'
+        year: STR_NUMERIC,
+        month: STR_LONG,
+        day: STR_NUMERIC,
+        weekday: STR_LONG
       })
+    },
+    weekdayHeaderFormat: {
+      // Format of the weekday names at the top of the calendar
+      // Note: This value is *not* to be placed in the global config
+      type: String,
+      // `short` is typically a 3 letter abbreviation,
+      // `narrow` is typically a single letter
+      // `long` is the full week day name
+      // Although some locales may override this (i.e `ar`, etc)
+      default: STR_SHORT,
+      validator: value => arrayIncludes([STR_LONG, STR_SHORT, STR_NARROW], value)
     }
   },
   data() {
@@ -271,18 +291,18 @@ export const BCalendar = Vue.extend({
     },
     computedLocale() {
       // Returns the resolved locale used by the calendar
-      return resolveLocale(concat(this.locale).filter(identity), 'gregory')
+      return resolveLocale(concat(this.locale).filter(identity), STR_GREGORY)
     },
     calendarLocale() {
       // This locale enforces the gregorian calendar (for use in formatter functions)
       // Needed because IE 11 resolves `ar-IR` as islamic-civil calendar
       // and IE 11 (and some other browsers) do not support the `calendar` option
       // And we currently only support the gregorian calendar
-      const fmt = new Intl.DateTimeFormat(this.computedLocale, { calendar: 'gregory' })
+      const fmt = new Intl.DateTimeFormat(this.computedLocale, { calendar: STR_GREGORY })
       const calendar = fmt.resolvedOptions().calendar
       let locale = fmt.resolvedOptions().locale
       /* istanbul ignore if: mainly for IE 11 and a few other browsers, hard to test in JSDOM */
-      if (calendar !== 'gregory') {
+      if (calendar !== STR_GREGORY) {
         // Ensure the locale requests the gregorian calendar
         // Mainly for IE 11, and currently we can't handle non-gregorian calendars
         // TODO: Should we always return this value?
@@ -384,9 +404,9 @@ export const BCalendar = Vue.extend({
         // Ensure we have year, month, day shown for screen readers/ARIA
         // If users really want to leave one of these out, they can
         // pass `undefined` for the property value
-        year: 'numeric',
-        month: '2-digit',
-        day: '2-digit',
+        year: STR_NUMERIC,
+        month: STR_2_DIGIT,
+        day: STR_2_DIGIT,
         // Merge in user supplied options
         ...this.dateFormatOptions,
         // Ensure hours/minutes/seconds are not shown
@@ -395,26 +415,37 @@ export const BCalendar = Vue.extend({
         minute: undefined,
         second: undefined,
         // Ensure calendar is gregorian
-        calendar: 'gregory'
+        calendar: STR_GREGORY
       })
     },
     formatYearMonth() {
       // Returns a date formatter function
       return createDateFormatter(this.calendarLocale, {
-        year: 'numeric',
-        month: 'long',
-        calendar: 'gregory'
+        year: STR_NUMERIC,
+        month: STR_LONG,
+        calendar: STR_GREGORY
       })
     },
     formatWeekdayName() {
-      return createDateFormatter(this.calendarLocale, { weekday: 'long', calendar: 'gregory' })
+      // Long weekday name for weekday header aria-label
+      return createDateFormatter(this.calendarLocale, {
+        weekday: STR_LONG,
+        calendar: STR_GREGORY
+      })
     },
     formatWeekdayNameShort() {
-      // Used as the header cells
-      return createDateFormatter(this.calendarLocale, { weekday: 'short', calendar: 'gregory' })
+      // Weekday header cell format
+      // defaults to 'short' 3 letter days, where possible
+      return createDateFormatter(this.calendarLocale, {
+        weekday: this.weekdayHeaderFormat || STR_SHORT,
+        calendar: STR_GREGORY
+      })
     },
     formatDay() {
-      return createDateFormatter(this.calendarLocale, { day: 'numeric', calendar: 'gregory' })
+      return createDateFormatter(this.calendarLocale, {
+        day: STR_NUMERIC,
+        calendar: STR_GREGORY
+      })
     },
     // Disabled states for the nav buttons
     prevDecadeDisabled() {
diff --git a/src/components/calendar/package.json b/src/components/calendar/package.json
index f64b8f18a43..89771389ac2 100644
--- a/src/components/calendar/package.json
+++ b/src/components/calendar/package.json
@@ -172,6 +172,11 @@
             "prop": "dateFormatOptions",
             "version": "2.6.0",
             "description": "Format object for displayed text string that is passed to `Intl.DateTimeFormat`"
+          },
+          {
+            "prop": "weekdayHeaderFormat",
+            "version": "2.12.0",
+            "description": "Format to use for the calendar weekday headings. Possible values are `long`, `short` (default), or `narrow`"
           }
         ],
         "events": [
diff --git a/src/components/form-datepicker/README.md b/src/components/form-datepicker/README.md
index 61e1cd5a269..5e161f97dca 100644
--- a/src/components/form-datepicker/README.md
+++ b/src/components/form-datepicker/README.md
@@ -439,6 +439,23 @@ Notes:
 - `year`, `month` and `day` will always be shown. If you need to leave out a value, set the property
   to `undefined`, although this is highly discouraged for accessibility reasons
 
+### Weekday name header format
+
+<span class="badge badge-info small">2.12.0+</span>
+
+The calendar weekday name header format defaults to `'short'`, which is typically a three-character
+abbreviation of the weekday, although some [locales](#internationalization) may override this. The
+format can be controlled via the prop `weekday-header-format` and accepts one of three values:
+
+- `'long'` the full weekday name (e.g. <samp>Tuesday</samp>). Handy when using a full width
+  calendar. Avoid using with the default calendar width.
+- `'short'` typically is a 2 or 3 letter abbreviation of the weekday name, depending on the selected
+  locale (e.g. "Tue").
+- `'narrow'` is typically a single character abbreviation (e.g., <samp>T</samp>). Two weekdays may
+  have the same narrow style for some locales (e.g. Tuesday and Thursday's narrow style are both
+  <samp>T</samp>). This can be handy for those locales that do not support the `'short'` format,
+  such as locales `'ar'` and `'fa'`.
+
 ### Date navigation button slots
 
 <span class="badge badge-info small">2.12.0+</span>
@@ -551,6 +568,7 @@ Saturday.
             labelHelp: 'Mit den Pfeiltasten durch den Kalender navigieren'
           },
           'ar-EG': {
+            weekdayHeaderFormat: 'narrow',
             labelPrevDecade: 'العقد السابق',
             labelPrevYear: 'العام السابق',
             labelPrevMonth: 'الشهر السابق',
@@ -566,6 +584,7 @@ Saturday.
             labelHelp: 'استخدم مفاتيح المؤشر للتنقل في التواريخ'
           },
           zh: {
+            weekdayHeaderFormat: 'narrow',
             labelPrevDecade: '过去十年',
             labelPrevYear: '上一年',
             labelPrevMonth: '上个月',
diff --git a/src/components/form-datepicker/form-datepicker.js b/src/components/form-datepicker/form-datepicker.js
index 3ede9083344..af73200e181 100644
--- a/src/components/form-datepicker/form-datepicker.js
+++ b/src/components/form-datepicker/form-datepicker.js
@@ -1,4 +1,5 @@
 import Vue from '../../utils/vue'
+import { arrayIncludes } from '../../utils/array'
 import { BVFormBtnLabelControl, dropdownProps } from '../../utils/bv-form-btn-label-control'
 import { getComponentConfig } from '../../utils/config'
 import { createDate, constrainDate, formatYMD, parseYMD } from '../../utils/date'
@@ -6,7 +7,7 @@ import { isUndefinedOrNull } from '../../utils/inspect'
 import { pick } from '../../utils/object'
 import idMixin from '../../mixins/id'
 import { BButton } from '../button/button'
-import { BCalendar } from '../calendar/calendar'
+import { BCalendar, STR_LONG, STR_NARROW, STR_NUMERIC, STR_SHORT } from '../calendar/calendar'
 import { BIconCalendar, BIconCalendarFill } from '../../icons/icons'
 
 const NAME = 'BFormDatepicker'
@@ -240,14 +241,26 @@ const propsMixin = {
     },
     dateFormatOptions: {
       // `Intl.DateTimeFormat` object
+      // Note: This value is *not* to be placed in the global config
       type: Object,
       default: () => ({
-        year: 'numeric',
-        month: 'long',
-        day: 'numeric',
-        weekday: 'long'
+        year: STR_NUMERIC,
+        month: STR_LONG,
+        day: STR_NUMERIC,
+        weekday: STR_LONG
       })
     },
+    weekdayHeaderFormat: {
+      // Format of the weekday names at the top of the calendar
+      // Note: This value is *not* to be placed in the global config
+      type: String,
+      // `short` is typically a 3 letter abbreviation,
+      // `narrow` is typically a single letter
+      // `long` is the full week day name
+      // Although some locales may override this (i.e `ar`, etc)
+      default: STR_SHORT,
+      validator: value => arrayIncludes([STR_LONG, STR_SHORT, STR_NARROW], value)
+    },
     // Dark mode
     dark: {
       type: Boolean,
@@ -328,7 +341,8 @@ export const BFormDatepicker = /*#__PURE__*/ Vue.extend({
         labelCalendar: self.labelCalendar,
         labelNav: self.labelNav,
         labelHelp: self.labelHelp,
-        dateFormatOptions: self.dateFormatOptions
+        dateFormatOptions: self.dateFormatOptions,
+        weekdayHeaderFormat: self.weekdayHeaderFormat
       }
     },
     computedLang() {
diff --git a/src/components/form-datepicker/package.json b/src/components/form-datepicker/package.json
index 7c05c0e0751..2f07d5f3982 100644
--- a/src/components/form-datepicker/package.json
+++ b/src/components/form-datepicker/package.json
@@ -268,6 +268,11 @@
             "prop": "dateFormatOptions",
             "version": "2.6.0",
             "description": "Format object for displayed text string that is passed to `Intl.DateTimeFormat`"
+          },
+          {
+            "prop": "weekdayHeaderFormat",
+            "version": "2.12.0",
+            "description": "Format to use for the calendar weekday headings. Possible values are `long`, `short` (default), or `narrow`"
           }
         ],
         "events": [