diff --git a/addons/mail/static/src/models/attachment/attachment.js b/addons/mail/static/src/models/attachment/attachment.js
index b25a254fbc0..58763f29661 100644
--- a/addons/mail/static/src/models/attachment/attachment.js
+++ b/addons/mail/static/src/models/attachment/attachment.js
@@ -299,7 +299,7 @@ registerModel({
         attachmentLists: many2many('AttachmentList', {
             inverse: 'attachments',
         }),
-        attachmentViewer: many2many('AttachmentViewer', {
+        attachmentViewers: many2many('AttachmentViewer', {
             inverse: 'attachments',
         }),
         checksum: attr(),
diff --git a/addons/mail/static/src/models/attachment_list/attachment_list.js b/addons/mail/static/src/models/attachment_list/attachment_list.js
index 10df15719d8..c8194f12881 100644
--- a/addons/mail/static/src/models/attachment_list/attachment_list.js
+++ b/addons/mail/static/src/models/attachment_list/attachment_list.js
@@ -83,7 +83,7 @@ registerModel({
         /**
          * Determines the attachment viewers displaying this attachment list (if any).
          */
-        attachmentViewer: one2many('AttachmentViewer', {
+        attachmentViewers: one2many('AttachmentViewer', {
             inverse: 'attachmentList',
             isCausal: true,
         }),
diff --git a/addons/mail/static/src/models/attachment_viewer/attachment_viewer.js b/addons/mail/static/src/models/attachment_viewer/attachment_viewer.js
index f4ea2429a19..35b691cf01e 100644
--- a/addons/mail/static/src/models/attachment_viewer/attachment_viewer.js
+++ b/addons/mail/static/src/models/attachment_viewer/attachment_viewer.js
@@ -40,12 +40,12 @@ registerModel({
         }),
         attachment: many2one('mail.attachment'),
         attachmentList: many2one('AttachmentList', {
-            inverse: 'attachmentViewer',
+            inverse: 'attachmentViewers',
             readonly: true,
             required: true,
         }),
         attachments: many2many('mail.attachment', {
-            inverse: 'attachmentViewer',
+            inverse: 'attachmentViewers',
             related: 'attachmentList.viewableAttachments',
         }),
         /**