| Title | Listen | Sheet Music |
| O Antiphons | | |
| O Arise, My Beloved | | |
| O Beauty, Ever Ancient | |  |
| O Bless the Lord | | |
| O Bless the Lord | | |
| O Bless the Lord, My Soul | | |
| O Bless the Lord, My Soul | | |
| O Blessed Are Those | | |
| O Blessed Mary | |  |
| O Blessed Queen of Mercy | |  |
| O Breathe on Me, O Breath of God | | |
| O Chosen One | |  |
| O Christ upon the Cross of War | | |
| O Christ, Bright Sun of Justice | | |
| O Christ, in Your Pity | | |
| O Christ, Our Teacher | | |
| O Christ, Son of the Living God | |  |
| O Christ, the Healer | | |
| O Christ, Unshielded and Unspared | | |
| O Christ, You Came | | |
| O Christ, You Reign in Splendor Robed | | |
| O Christ, You Reign in Splendor Robed | |  |
| O Christ, You Speak the Names of God | | |
| O Christ, You Speak the Names of God | | |
| O Christe Domine Jesu | | |
| O Christmas Tree / Away in a Manger | | |
| O Come Bless the Lord | |  |
| O Come to Meet Her, Saints of God | | |
| O Come to Meet Him, Saints of God | | |
| O Come, All Ye Faithful | | |
| O Come, All Ye Faithful | | |
| O Come, All Ye Faithful/Adeste Fideles | |  |
| O Come, Divine Messiah | | |
| O Come, Emmanuel | |  |
| O Come, Emmanuel | | |
| O Come, Let Us Follow | | |
| O Come, Little Children | | |
| O Come, Little Children | | |
| O Come, Little Children | | |
| O Come, Little Children | |  |
| O Come, O Come Emmanuel | |  |
| O Come, O Come Emmanuel | | |
| O Come, O Come, Emmanuel | |  |
| O Come, O Come, Emmanuel | | |
| O Crucified Messiah | |  |
| O Day of Peace That Dimly Shines | | |
| O Dayspring of the Long Sought Day | | |
| O Dearest Lord, Your Sacred Head | | |
| O Death, Where Is Your Power | |  |
| O Domine Jesu Christe | | |
| O Ephraim | | |
| O Faithful Cross | |  |
| O Father of Goodness | | |
| O Gentle Mother | |  |
| O Gentle Mother (Intro) | | |
| O God beyond All Praising | | |
| O God of Great Compassion | | |
| O God of Love | |  |
| O God of Love | | |
| O God of Past and Present | | |
| O God, Almighty Father | | |
| O God, Come and Save Us | | |
| O God, Come Home Among Us | | |
| O God, for You I Long | | |
| O God, Hear Our Prayer | | |
| O God, Hear Us | | |
| O God, Hear Us | | |
| O God, Hear Us / O Lord, Heal Us | | |
| O God, Let All the Nations | | |
| O God, Let All the Nations Praise You | | |
| O God, Let All the Nations Praise You! | | |
| O God, My God | | |
| O God, Nothing Can Take Us from Your Love | | |
| O God, Our Help in Ages Past | | |
| O God, Our Hope, Our Shield | | |
| O God, the Midday Sun Burns Hot | | |
| O God, Uphold My Life | | |
| O God, We Are Your Children | | |
| O God, You Are My God | | |
| O God, You Are Very Near | | |
| O God, You Flamed on Sinai's Height | | |
| O God, You Have Given Me Life | | |
| O God, You Search Me | |  |
| O Good Lord | | |
| O Gracious Father | | |
| O Gracious Light | |  |
| O Great Spirit | | |
| O Healing Light of Christ | |  |
| O Healing River | | |
| O Heavens, Open from Above | |  |
| O Heavens, Open from Above | | |
| O Heiland, Reiss die Himmel Auf | | |
| O Holy Mary | |  |
| O Holy Night | | |
| O Holy Night | | |
| O Holy Night | | |
| O Holy Night of Glory | |  |
| O How Amiable | |  |
| O How Beautiful | |  |
| O How Blest | |  |
| O How Do They Praise You | | |
| O How I Long To See | |  |
| O Jerusalem | | |
| O Jerusalem | | |
| O Jerusalem | | |
| O Jesus Christ, May Grateful Hymns Be Rising | | |
| O Jesus, Healer of Wounded Souls | |  |
| O Jesus, Joy of Loving Hearts | | |
| O Joyful Light | |  |
| O Lai Thôi Chúa Con Oi / Stay With Us, O Lord | | |
| O Lamm Gottes, Unschulding | | |
| O Lamm Gottes, Unschulding | | |
| O Let Your Light | |  |
| O Light of Christ | |  |
| O Little Town of Bethlehem | | |
| O Little Town of Bethlehem | | |
| O Little Town of Bethlehem | | |
| O Lord I Have Waited | | |
| O Lord My Strength | |  |
| O Lord of Darkness and of Light | | |
| O Lord of Life | | |
| O Lord, Have Mercy | | |
| O Lord, Heal Us | | |
| O Lord, Heal Us | | |
| O Lord, Heal Us (Lenten Verses) | |  |
| O Lord, Hear My Prayer | | |
| O Lord, I Am Not Worthy | | |
| O Lord, I Will Sing | |  |
| O Lord, My Shepherd | | |
| O Lord, Our God | | |
| O Lord, Our God | | |
| O Lord, Our God | | |
| O Lord, Our God How Wonderful Your Name | |  |
| O Lord, Our God, How Wonderful Your Name in All the Earth | | |
| O Lord, Save the Poor | | |
| O Love of God Incarnate | | |
| O Love of God/Amor de Dios | |  |
| O Love That Never Fails | | |
| O Loving God | |  |
| O Lux Beata Trinitas | | |
| O Magnum Mysterium | |  |
| O Magnum Mysterium | | |
| O Magnum Mysterium | |  |
| O Malhao | | |
| O Maria, Full of Sorrows | | |
| O Maria, Hear | | |
| O Maria, You Were Chosen | | |
| O Mary, Tell Us | | |
| O Mother of Jesus | | |
| O Mother of Jesus | |  |
| O Mother, Virgin Too | | |
| O My People | |  |
| O My People | |  |
| O My Soul, Bless the Lord | | |
| O Night That Is Brighter Than the Day | |  |
| O Poor Little Jesus | |  |
| O Praise the Lord | | |
| O Praise the Lord | | |
| O Praise The Lord: Gospel Acclamation | | |
| O Queen of Heaven | | |
| O Queen of Heaven | |  |
| O Redeemer | | |
| O Redeemer | |  |
| O Rest in the Lord | |  |
| O Risen Christ | | |
| O Sacrament Most Holy | | |
| O Sacrament Most Holy | | |
| O Sacred Head | |  |
| O Sacred Head, Surrounded | | |
| O Sacrum Convivium | |  |
| O Salutaris Hostia | | |
| O Salutarius Hostia / Tantum Ergo | | |
| O Sanctissima | |  |
| O Sanctissima | | |
| O Sanctissima/O Most Holy One/Mary, Full of Grace | | |
| O Saving Victim | | |
| O Saving Victim / O Salutaris Hostia | | |
| O Silence Sonorous with Word | |  |
| O Silence Sonorous with Word | | |
| O Silent God | | |
| O Sing a Joyous Carol | |  |
| O Spirit of the Living Lord | | |
| O Spirit of the Living Lord | | |
| O Splendor of God's Glory | | |
| O Sweet and Sacred Feast | |  |
| O Taste and See | | |
| O Taste and See | |  |
| O Taste and See | |  |
| O the Deep Joy | | |
| O the Depth of Love Divine | |  |
| O Tree of Life, By Running Stream | | |
| O Trinity of Blessed Light | | |
| O Veni, Sancte Spiritus | |  |
| O Virtus Sapientiae | | |
| O What a Walk | | |
| O Wondrous Sight! O Vision Fair | |  |
| O Word of God | |  |
| O Word of God, Before the Light | | |
| O Word of God, In Flesh You Came | | |
| O You Great and Mighty Chief | | |
| Od Lo Ahawti Dai | | |
| Of Christ Our King | | |
| Of My Hands | | |
| Of the Father's Love / All Creatures | | |
| Of The Father's Love Begotten | | |
| Of the Father's Love Begotten | |  |
| Of the Father's Love Begotten | | |
| Ofertorio de la Espera | | |
| Ofertorio Nicaragüense | | |
| Ofrenda del Corazón | | |
| Oh Criaturas del Señor | | |
| Oh Cruz Fiel | | |
| Oh Cruz Fiel | | |
| Oh Cruz Fiel y Venerable | | |
| Oh Cruz, Te Adoramos | | |
| Oh Dios, Crea en Mí un Corazón Puro | | |
| Oh Dios, Crea en Mí un Corazón Puro | | |
| Oh Dios, Crea en Mí/Create in Me | | |
| Oh Dios, que Te Alaben los Pueblos | | |
| Oh Dios, que Te Alaben los Pueblos (Salmo 66) | |  |
| Oh Jesús, Oh Buen Pastor | | |
| Oh María, Madre Mía | | |
| Oh Mi Dios, Crea en Mí | | |
| Oh Puertas | | |
| Oh Santísima | | |
| Oh Señor, Delante de Ti | | |
| Oh Señor, No Soy Digno | | |
| Oh Susana! | | |
| Oh Ven, Oh Ven, Emmanuel | | |
| Oh Virgen de Guadalupe | | |
| Oh Yes, Lord Jesus Lives | | |
| Oh, Happy One | | |
| Oh, How Good | | |
| Oh, How I Love Jesus | | |
| Oh, How Lovely | | |
| Oh, How the Longing Heart Like Incense Curls | | |
| Oh, My Lord, I Long for You | | |
| Oh, Sing to the Lord | | |
| Oh, The Love of My Lord | | |
| Oh, When the Saints | | |
| Oh, Who Can Know the Mind of God | | |
| Oh, Won't You Sit Down | |  |
| Oí Tu Voz | | |
| Ojalá Escuchemos Su Voz | | |
| Ojalá Escuchen Hoy la Voz del Señor | | |
| Ojalá Escuchen Hoy la Voz del Señor | | |
| Ojalá Escuchen Hoy la Voz del Señor | | |
| Ojalá Escuchen Hoy la Voz del Señor | | |
| Ojalá Escuchen Hoy Su Voz | | |
| Ojalá Escuchen Hoy Su Voz | | |
| Ojalá Escuchen Hoy Su Voz (Salmo 94) | | |
| Oklahoma Remembers | | |
| On a Bright Day Next Week | | |
| On a Mission / En Mission / Y Me Da una Misión | |  |
| On Christmas Night | |  |
| On Christmas Night | |  |
| On Christmas Night All Christians Sing | | |
| On Eagle's Wings/En Sus Alas | |  |
| On Fire with the Lord | | |
| On Jordan's Bank | |  |
| On Jordan's Bank | |  |
| On My Knees | | |
| On Our Journey to the Kingdom | |  |
| On Our Journey to You | | |
| On Pentecost They Gathered | | |
| On That Holy Mountain | | |
| On the Day I Called | |  |
| On the Day I Called | | |
| On the Day I Called | | |
| On the Day of Your Great Coming | | |
| On the Jericho Highway | | |
| On the Lips of an Angel/Ave Maria | |  |
| On the Wings of Eagles | |  |
| On This Bright Easter Morn | |  |
| On This Day | |  |
| On This Day | | |
| On This Day | |  |
| On This Day, O Beautiful Mother | | |
| On This Day, the First of Days | | |
| On This Most Holy Day | |  |
| On This Mountain | |  |
| Once and for All | | |
| Once in Royal David's City | |  |
| Once in Royal David's City | | |
| Once More Pilate Went Out | | |
| One Bread | | |
| One Bread We Break | | |
| One Bread, One Body | |  |
| One Bread, One Cup | |  |
| One Day | | |
| One Day in Winter | | |
| One Does Not Live on Bread Alone | | |
| One Does Not Live on Bread Alone | | |
| One Does Not Live on Bread Alone, but on Every World that Comes Forth from the Mouth of God | | |
| One Does Not Live on Bread Alone, but on Every World that Comes Forth from the Mouth of God | | |
| One Faith, One Hope, One Lord | | |
| One in Body, Heart and Mind | |  |
| One in Christ | |  |
| One in Christ Jesus | | |
| One in Faith | | |
| One Life | | |
| One Lord | | |
| One Love | | |
| One Love Released | |  |
| One More Hug | | |
| One Mother to Another | |  |
| One Spirit, One Church | |  |
| One Thing Have I Asked of the Lord (Psalm 27) | |  |
| One Thing I Ask | | |
| One Thing I Ask | |  |
| One Thing I Hope for | |  |
| One Tiny Child | |  |
| One with the Risen Lord | |  |
| Only a Shadow | |  |
| Only in God | |  |
| Only in God | |  |
| Only the Shepherds | |  |
| Only This I Want | |  |
| Only Your Love | | |
| Open My Eyes | |  |
| Open My Eyes/Amazing Grace | |  |
| Open Our Eyes
| | |
| Open Our Eyes This Day! | | |
| Open Our Hearts | | |
| Open Our Hearts, O Lord, to Listen to the Words of Your Son | | |
| Open the Eyes of My Heart | | |
| Open the Gates | |  |
| Open Your Eyes and See | | |
| Opening Dialogue | |  |
| Opening Dialogue (Invitatory) | | |
| Opening Dialogue (Lucernarium) | | |
| Opening Prayer (Advent) | | |
| Opening Prayer (Lent) | | |
| Opening Verse (Day/Night) | | |
| Opening Verse (Evening) | | |
| Opening Verse (Morning Prayer) | | |
| Oración | | |
| Oración al Cristo del Calvario | | |
| Oración de los Esposos | |  |
| Oración de los Fieles | | |
| Oración de los Fieles | | |
| Oración de los Fieles | | |
| Oración en la Cruz | | |
| Oración Universal | | |
| Oriens Alleluia | | |
| Os Doy un Mandamiento Nuevo | | |
| Other Eucharisitic Acclamations | | |
| Otros Belenes | | |
| Our Blessing Cup | |  |
| Our Blessing Cup | |  |
| Our Blessing Cup | | |
| Our Blessing Cup | |  |
| Our Blessing-Cup | |  |
| Our Blessing-Cup (Psalm 116) | |  |
| Our Blessing-Cup (Psalm 116) | |  |
| Our Blessing-cup is a Communion with the Blood of Christ | | |
| Our Blessing-Cup Is a Communion with the Blood of Christ | | |
| Our Comfort and Strength | | |
| Our Daily Bread | |  |
| Our Eyes are Fixed on the Lord, Pleading For His Mercy | | |
| Our Eyes Are Fixed on the Lord, Pleading for His Mercy | | |
| Our Eyes Are Turned to the Lord | | |
| Our Father | | |
| Our Father | | |
| Our Father | | |
| Our Father | | |
| Our Father | | |
| Our Father | | |
| Our Father | |  |
| Our Father (Evening) | | |
| Our Father, We Have Wandered | | |
| Our God Has Done Great Things | | |
| Our God Is a God of Love | | |
| Our God Is Glory | |  |
| Our God Is Good | |  |
| Our God Is Good | | |
| Our God Is Here | |  |
| Our God Is Near | | |
| Our God Is Our God | | |
| Our God Provides | | |
| Our God Reigns | | |
| Our Help | |  |