MB Relationships


MB Relationships helps you create relationships between posts, pages, custom post type, terms and users. The plugin is lightweight and optimized for database and query performance.

The plugin allows you to create connections from posts to posts, posts to pages and so on. Then you can perform corresponding queries to retrieve posts that are connected to or from given posts.

It supports reciprocal and bi-directional relationships.

Why Do You Need Posts To Posts Relationships In WordPress?

Post relationships is a missing part in WordPress. The only “built-in” way that mimic the post relationship in WordPress is the post_parent for pages where you can create many child pages of a page (a one-to-many relationship). Unfortunately, that’s available for pages and hierarchical post types only. Besides, it’s not many-to-many relationship.

Below are some examples of posts to posts relationships that might help you see the benefit of this feature:

Creating Related Posts In WordPress

The simplest example is to manually create related posts in your WordPress website. When you edit a post, you can select posts that have similar or related content and display them in the frontend for further reading.

You can also query backward: displaying posts that link to the being read post as a reference to provide more information to your readers. With this, you don’t need a WordPress related posts plugin anymore.

Example: Events And Bands

Suppose you have two custom post types, event and band, where:

  • In each event there may be multiple bands, and
  • Each band can participate in many events.

If people want to buy tickets, they could search for events in their location and see what bands are playing on a given date, or they could search for bands they like and see what date they are playing near their location.

In this example, we have created many-to-many relationships between events and bands.

Bi-directional relationships

MB Relationships allows you to create bi-directional connections. You will be able to query back and forth without any problem.

The data is stored in the database as a pair of (from_id, to_id), thus making it independent from either side.

Besides, for each side, there’s a meta box that shows what are connected from/to. So you don’t have to worry about the direction of the connection anymore.

An Alternative For The Posts 2 Posts Plugin (P2P Plugin)

MB Relationships is very much inspired by the popular plugin Posts 2 Posts which is not maintained anymore. We have taken the idea and made some improvements. The codebase and data structure is very similar.

Plugin features

  • Simple APIs: the plugin provides simple APIs for registering relationships and retrieving connected items. It integrates with existing WordPress APIs such as WP_Query,get_terms and get_users. See documentation for more information.
  • Uses custom relationship table to store relationships. That helps optimize the database storage and query performance.
  • You can create relationships between any kind of content in WordPress: posts to posts, posts to users, etc. For posts to terms and posts to users, it’s required the MB Term Meta and MB User Meta.
  • Supports creating reciprocal relationships (posts-posts, users-users, …).
  • Supports creating bi-directional relationships and easily query them.
  • Display connected items easily with shortcode.
  • Extremely lightweight and fast.

Plugin Links

This plugin is a free extension of Meta Box plugin, which is a powerful, professional solution to create custom fields and custom meta boxes for WordPress websites. Using MB Relationships in combination with other extensions will help you manage any content types in WordPress easily and make your website more professional.

You might also like

If you like this plugin, you might also like our other WordPress products:

  • Meta Box – A powerful WordPress plugin for creating custom post types and custom fields.
  • Slim SEO – A fast, lightweight and full-featured SEO plugin for WordPress with minimal configuration.
  • Slim SEO Schema – An advanced, powerful and flexible plugin to add schemas to WordPress.
  • Slim SEO Link Manager – Build internal link easier in WordPress with real-time reports.
  • GretaThemes – Free and premium WordPress themes that clean, simple and just work.
  • Auto Listings – A car sale and dealership plugin for WordPress.


  • “Connects To” meta box
  • “Connected From” meta box
  • Database structure


You need to install Meta Box plugin first

  • Go to Plugins | Add New and search for Meta Box
  • Click Install Now button to install the plugin
  • After installing, click Activate Plugin to activate the plugin

Install MB Relationships extension

  • Go to Plugins | Add New and search for MB Relationships
  • Click Install Now button to install the plugin
  • After installing, click Activate Plugin to activate the plugin


Jeddi 30, 2022
The plugin itself seems powerful. However I wouldn’t know because it’s very difficult to use unless you’re a developer. Be aware that there is no UI with this plugin, it adds a capability to your site but you have to handle code to use it. The documentation is written for developers. Even if you’re willing to learn, the doc provides little examples; mostly short snippets that you must know where and how to use. To top it all, the support team answers novice questions mainly by redirecting to the documentation, and make it clear that they’re not willing to help you below a certain developing skill level. So unless 1) you’re a developer, 2) you are willing to hire one to use this plugin, or 3) you use a page builder that integrates with Metabox and MB Relationships specifically (Oxygen for example), I suggest you pass. Nothing wrong with making plugins for developers only, it’s a design and business decision by Metabox. But the plugin presentation makes it seem fairly beginner-friendly. It is not, you should be aware of it.
Hamal 19, 2020
The from> to> relationship abilities of this plugin are unique as it writes them in the database. Bravo to the developers!
Dáliw 4, 2019 1 reply
Sadly, there is no support for this plugin. I posted a bug report here: https://wordpress.org/support/topic/sort-order-in-the-metabox-lost-or-reversed/ and here: https://github.com/wpmetabox/mb-relationships/issues/13 more than two weeks ago, but nobody bothers to reply… Edit 1: +2 stars for replying to the bug report. Edit 2: +2 stars for fixing the bug and now working really well.
Read all 4 reviews

Contributors & Developers

“MB Relationships” is open source software. The following people have contributed to this plugin.


“MB Relationships” has been translated into 3 locales. Thank you to the translators for their contributions.

Translate “MB Relationships” into your language.

Interested in development?

Browse the code, check out the SVN repository, or subscribe to the development log by RSS.


1.12.2 – 2024-05-16

  • Set default field label for clarity and to work with Oxygen builder.

1.12.1 – 2024-04-11

  • Fix admin filter compatibility with Visual Composer

1.12.0 – 2024-03-25

  • Add admin filter in the “edit” posts screen to filter posts by relationships. To enable this feature, please add 'admin_filter' => true to a side of the relationship settings. Works only for posts.
  • Fix API::each_connected() not working

1.11.3 – 2023-11-16

  • Add a config constant MB_RELATIONSHIPS_DELETE_DATA to delete plugin data when uninstalling (#74)
  • Fix getting users not following the order in the admin (#73)

1.11.2 – 2023-09-18

  • Fix error when split query is true, occurs with recent update of Object Cache Pro.

1.11.1 – 2023-05-10

  • Fix draft items not being returned consistently

1.11.0 – 2022-12-22

  • Add REST API support. See docs for usage. Props @macbookandrew.

1.10.11 – 2022-03-08

  • Shortcode: support removing the link to items with link="false"

1.10.10 – 2021-12-14

  • Fix php notice when delete an object
  • Fix each_connected does not working for users

1.10.9 – 2021-09-18

  • Fix deleting post objects, relationships are not deleted

1.10.8 – 2021-08-12

  • Fix querying by multiple relationships not working when a relationship has no connections.

1.10.7 – 2021-08-05

  • Fix querying by multiple relationships showing a warning.

1.10.6 – 2021-07-14

  • Fix reciprocal relationships not working with terms.
  • Fix querying multiple relationships with relation AND not working.
  • Fix bug when a post and a user have the same ID.
  • Fix admin columns, API and WP_Query not returning posts when the post type has exclude_from_search = true.
  • Improve performance by not checking relationship table each time a page loads.

1.10.5 – 2020-08-17

  • Fix SQL error when relationship ID contains dashes

1.10.4 – 2020-07-28

  • Fix non-reciprocal relationships break multiple relationship query
  • Allow reciprocal relationships for users, terms

1.10.3 – 2020-07-07

  • Fix reciprocal post query doesn’t work with custom ‘orderby’ param

1.10.2 – 2020-07-06

  • Fix wrong table prefix when getting reciprocal relationships
  • Add hooks for add, delete relationships

1.10.1 – 2020-06-18

  • Add filter for relationship settings
  • Fix reciprocal not follow the order of the admin

1.10.0 – 2020-04-22

  • Add APIs to get all relationships and relationships settings

1.9.2 – 2020-04-17

  • Fix each_connected not working

1.9.1 – 2020-04-08

  • Fix query of the storage get function for reciprocal relationships
  • Fix each_connected not working

1.9.0 – 2020-02-19

  • Add link parameter to admin_column which accepts view (default), edit or false (no link).
  • Fix duplicated connections.

1.8.0 – 2020-01-05

  • Add support for reciprocal relationships
  • Add mb_relationships_registered hook

1.7.1 – 2019-11-01

  • Fix creating table error due to empty collate

1.7.0 – 2019-09-18

  • Add a separate field array for field settings
  • Add order_from and order_to to API::add method

1.6.1 – 2019-07-17

  • Make hidden param work for to side
  • Remove duplicate from query

1.6.0 – 2019-02-25

  • Added support for querying by multiple relationships. See docs for details.
  • Extracted admin columns and meta boxes into their own classes
  • Renamed files and classes for clarity

1.5.0 – 2018-12-19

  • Fixed incorrect order of items when changing order of connected items.
  • Changed the database structure by adding order_from and order_to columns to track order of items.
  • Removed reference to global $wpdb and use the global variable directly. This prevents serialize objects in some unexpected situations.

1.4.1 – 2018-10-26

  • Fixed cannot query for posts excluded from search.
  • Fixed not showing entries in admin columns.

1.4.0 – 2018-08-24

  • Added ‘closed’ and ‘autosave’ param to relationship meta boxes.
  • Fixed indirect variable access in PHP 5.x.

1.3.2 – 2018-07-02

  • Reverted the 'post_type' => 'any' as it relates to many queries.

1.3.1 – 2018-07-02

  • Remove 'post_type' => 'any' in the query for relationship, which causes unexpected behaviour with post types that have 'exclude_from_search' => true. Developers should always set post_type in their queries. See https://bit.ly/2lPvnPk.

1.3.0 – 2018-05-25

  • Added support for admin columns. See documentation for details.

1.2.0 – 2018-04-27

  • Added API to get siblings items.

1.1.2 – 2018-03-08

  • Fixed output of related posts with the same order as in the backend.

1.1.1 – 2018-02-27

  • Made clones sortable


  • Added meta box for selecting ‘from’ objects
  • Added CRUD API for relationships


  • Initial version