| January | New Year’s Day | 2023-01-01 Sunday | bank holidays |
| New Year’s Day | 2023-01-02 Monday | bank holidays | |
| 2nd January (substitute day) | 2023-01-03 Tuesday | Local holiday | |
| Epiphany | 2023-01-06 Friday | Christian festivals | |
| Orthodox Christmas Day | 2023-01-07 Saturday | Orthodox Festival | |
| Orthodox New Year | 2023-01-14 Saturday | Orthodox Festival | |
| Chinese New Year | 2023-01-22 Sunday | Holidays or anniversaries | |
| Burns Night | 2023-01-25 Wednesday | Local festival | |
| February | Tu Bishvat/Tu B’Shevat | 2023-02-06 Monday | Judaism festival |
| Valentine’s Day | 2023-02-14 Tuesday | Holidays or anniversaries | |
| Isra and Mi’raj | 2023-02-18 Saturday | Muslim festivals | |
| Shrove Tuesday/Mardi Gras | 2023-02-21 Tuesday | Christian festivals | |
| Carnival / Ash Wednesday | 2023-02-22 Wednesday | Christian festivals | |
| Mar. | St. David’s Day | 2023-03-01 Wednesday | Holidays or anniversaries |
| Purim | 2023-03-07 Tuesday | Judaism festival | |
| St. Patrick’s Day | 2023-03-17 Friday | Local holiday | |
| Mothering Sunday | 2023-03-19 Sunday | Holidays or anniversaries | |
| First Day of Ramadan | 2023-03-23 Thursday | Muslim festivals | |
| April | Palm Sunday | 2023-04-02 Sunday | Christian festivals |
| Maundy Thursday | 2023-04-06 Thursday | Christian festivals | |
| Passover (first day) | 2023-04-06 Thursday | Judaism festival | |
| Good Friday | 2023-04-07 Friday | bank holidays | |
| Holy Saturday | 2023-04-08 Saturday | Christian festivals | |
| Orthodox Easter Day | 2023-04-09 Sunday | Christian festivals | |
| Orthodox Easter Monday | Orthodox Easter Monday | Holidays or anniversaries | |
| Orthodox Easter Monday | 2023-04-10 Monday | Common local holidays | |
| Last Day of Passover | 2023-04-13 Thursday | Judaism festival | |
| Orthodox Good Friday | 2023-04-14 Friday | Orthodox Festival | |
| Orthodox Holy Saturday | 2023-04-15 Saturday | Orthodox Festival | |
| Orthodox Easter | 2023-04-16 Sunday | Orthodox Festival | |
| Orthodox Easter Monday | 2023-04-17 Monday | Orthodox Festival | |
| Laylatul Qadr (Night of Power) | 2023-04-17 Monday | Muslim festivals | |
| Yom HaShoah | 2023-04-18 Tuesday | Jewish Memorial Festival | |
| Stephen Lawrence Day | 2023-04-22 Saturday | Holidays or anniversaries | |
| Eid ul Fitr | 2023-04-22 Saturday | Muslim festivals | |
| St George’s Day | 2023-04-23 Sunday | Holidays or anniversaries | |
| Shakespeare Day | 2023-04-23 Sunday | Holidays or anniversaries | |
| Yom Ha’atzmaut | 2023-04-26 Wednesday | Judaism festival | |
| May | Early May Bank Holiday | 2023-05-01 Monday | bank holidays |
| Lag BaOmer | 2023-05-09 Tuesday | Judaism festival | |
| Ascension Day | 2023-05-18 Thursday | Christian festivals | |
| Shavuot | 2023-05-26 Friday | Christian festivals | |
| Pentecost | 2023-05-28 Sunday | Christian festivals | |
| Whit Monday | 2023-05-29 Monday | Christian festivals | |
| Spring Bank Holiday | 2023-05-29 Monday | bank holidays | |
| June | Trinity Sunday | 2023-06-04 Sunday | Christian festivals |
| Corpus Christi | 2023-06-08 Thursday | Christian festivals | |
| Queen’s Birthday | 2023-06-10 Saturday | Holidays or anniversaries | |
| Father’s Day | 2023-06-18 Sunday | Holidays or anniversaries | |
| Windrush Day | 2023-06-22 Thursday | Holidays or anniversaries | |
| Eid ul Adha | 2023-06-29 Thursday | Muslim festivals | |
| July | Battle of the Boyne | 2023-07-12 Wednesday | Local holiday |
| Muharram/Islamic New Year | 2023-07-19 Wednesday | Muslim festivals | |
| Tisha B’Av | 2023-07-27 Thursday | Judaism festival | |
| Ashura | 2023-07-28 Friday | Muslim festivals | |
| August | Summer Bank Holiday | 2023-08-07 Monday | Common local holidays |
| Assumption of Mary | 2023-08-15 Tuesday | Christian festivals | |
| Summer Bank Holiday | 2023-08-28 Monday | Common local holidays | |
| September | Rosh Hashana | 2023-09-16 Saturday | Judaism festival |
| Yom Kippur | 2023-09-25 Monday | Judaism festival | |
| Milad un Nabi (Mawlid) | 2023-09-27 Wednesday | Muslim festivals | |
| First Day of Sukkot | 2023-09-30 Saturday | Judaism festival | |
| October | Feast of St Francis of Assisi | 2023-10-04 Wednesday | Christian festivals |
| Last Day of Sukkot | 2023-10-06 Friday | Judaism festival | |
| Shmini Atzeret | 2023-10-07 Saturday | Judaism festival | |
| Simchat Torah | 2023-10-08 Sunday | Judaism festival | |
| Halloween | 2023-10-31 Tuesday | Holidays or anniversaries | |
| November | All Saints Day | 2023-11-01 Wednesday | Christian festivals |
| All Souls’ Day | 2023-11-02 Thursday | Christian festivals | |
| Guy Fawkes Day | 2023-11-05 Sunday | Holidays or anniversaries | |
| Remembrance Sunday | 2023-11-12 Sunday | Holidays or anniversaries | |
| Diwali (For Hindus only) | 2023-11-13 Monday | Indian holiday | |
| St Andrew’s Day | 2023-11-30 Thursday | Local holiday | |
| December | First Sunday of Advent | 2023-12-03 Sunday | Holidays or anniversaries |
| Immaculate Conception | 2023-12-08 Friday | Christian festivals | |
| Chanukah/Hanukkah (first day) | 2023-12-08 Friday | Judaism festival | |
| Last day of Hanukkah | 2023-12-15 Friday | Judaism festival | |
| Christmas Eve | 2023-12-24 Sunday | Holidays or anniversaries | |
| Boxing Day | 2023-12-26 Tuesday | bank holidays | |
| New Year’s Eve | 2023-12-31 Sunday | Holidays or anniversaries |
