diff --git a/lib/Db/OrganizationFolderMember.php b/lib/Db/OrganizationFolderMember.php
new file mode 100644
index 0000000..24c12d0
--- /dev/null
+++ b/lib/Db/OrganizationFolderMember.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace OCA\OrganizationFolders\Db;
+
+use JsonSerializable;
+use OCA\OrganizationFolders\Interface\TableSerializable;
+
+use OCP\AppFramework\Db\Entity;
+
+use OCA\OrganizationFolders\Enum\OrganizationFolderMemberPermissionLevel;
+use OCA\OrganizationFolders\Enum\PrincipalType;
+use OCA\OrganizationFolders\Model\Principal;
+
+class OrganizationFolderMember extends Entity implements JsonSerializable, TableSerializable {
+	protected $organizationFolderId;
+	protected $permissionLevel;
+	protected $principalType;
+    protected $principalId;
+    protected $createdTimestamp;
+	protected $lastUpdatedTimestamp;
+	
+	public function __construct() {
+		$this->addType('organizationFolderId','integer');
+		$this->addType('permissionLevel','integer');
+        $this->addType('principalType','integer');
+        $this->addType('createdTimestamp','integer');
+		$this->addType('lastUpdatedTimestamp','integer');
+	}
+	
+	public function getPrincipal(): Principal {
+		return new Principal(PrincipalType::from($this->principalType), $this->principalId);
+	}
+
+	public function setPrincipal(Principal $principal) {
+        $principalType = $principal->getType();
+        if($principalType === PrincipalType::GROUP || $principalType === PrincipalType::ROLE) {
+		    $this->setPrincipalType($principalType->value);
+        } else {
+            throw new \Exception("individual users are not allowed as organization folder members");
+        }
+
+        $this->setPrincipalId($principal->getId());
+	}
+
+    public function setPermissionLevel(int $permissionLevel) {
+        if($permissionLevel >= 1 && $permissionLevel <= 3) {
+			if ($permissionLevel === $this->permissionLevel) {
+				// no change
+				return;
+			}
+
+			$this->markFieldUpdated("permissionLevel");
+            $this->permissionLevel = $permissionLevel;
+        } else {
+            throw new \Exception("invalid organization folder member permission level");
+        }
+    }
+
+    public function jsonSerialize(): array {
+		return [
+			'id' => $this->id,
+			'organizationFolderId' => $this->organizationFolderId,
+			'permissionLevel' => $this->permissionLevel,
+			'principal' => $this->getPrincipal(),
+            'createdTimestamp' => $this->createdTimestamp,
+			'lastUpdatedTimestamp' => $this->lastUpdatedTimestamp,
+		];
+	}
+
+    public function tableSerialize(?array $params = null): array {
+		return [
+			'Id' => $this->id,
+			'Organization Folder Id' => $this->organizationFolderId,
+			'Permission Level' => OrganizationFolderMemberPermissionLevel::from($this->permissionLevel)->name,
+			'Principal Type' => PrincipalType::from($this->principalType)->name,
+            'Principal Id' => $this->principalId,
+            'Created' => $this->createdTimestamp,
+			'LastUpdated' => $this->lastUpdatedTimestamp,
+		];
+	}
+}
diff --git a/lib/Db/OrganizationFolderMemberMapper.php b/lib/Db/OrganizationFolderMemberMapper.php
new file mode 100644
index 0000000..11f3a86
--- /dev/null
+++ b/lib/Db/OrganizationFolderMemberMapper.php
@@ -0,0 +1,72 @@
+<?php
+
+namespace OCA\OrganizationFolders\Db;
+
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\AppFramework\Db\Entity;
+use OCP\AppFramework\Db\QBMapper;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\IDBConnection;
+
+class OrganizationFolderMemberMapper extends QBMapper {
+	public const ORGANIZATIONFOLDER_MEMBERS_TABLE = "organizationfolders_members";
+
+	public function __construct(IDBConnection $db) {
+		parent::__construct($db, self::ORGANIZATIONFOLDER_MEMBERS_TABLE, OrganizationFolderMember::class);
+	}
+
+	/**
+	 * @param int $id
+	 * @return Entity|OrganizationFolderMember
+	 * @throws \OCP\AppFramework\Db\MultipleObjectsReturnedException
+	 * @throws DoesNotExistException
+	 */
+	public function find(int $id): OrganizationFolderMember {
+		/* @var $qb IQueryBuilder */
+		$qb = $this->db->getQueryBuilder();
+
+		$qb->select('*')
+			->from(self::ORGANIZATIONFOLDER_MEMBERS_TABLE)
+			->where($qb->expr()->eq('id', $qb->createNamedParameter($id, IQueryBuilder::PARAM_INT)));
+		
+		return $this->findEntity($qb);
+	}
+
+	/**
+	 * @param int $organizationFolderId
+     * @param array{permissionLevel: int, principalType: int} $filters
+	 * @return array
+	 * @psalm-return OrganizationFolderMember[]
+	 */
+	public function findAll(int $organizationFolderId, array $filters = []): array {
+		/* @var $qb IQueryBuilder */
+		$qb = $this->db->getQueryBuilder();
+
+		$qb->select('*')
+			->from(self::ORGANIZATIONFOLDER_MEMBERS_TABLE)
+			->where($qb->expr()->eq('organization_folder_id', $qb->createNamedParameter($organizationFolderId, IQueryBuilder::PARAM_INT)));
+
+        if(isset($filters["permissionLevel"])) {
+            $qb->andWhere($qb->expr()->eq('permission_level', $qb->createNamedParameter($filters["permissionLevel"], IQueryBuilder::PARAM_INT)));
+        }
+
+        if(isset($filters["principalType"])) {
+            $qb->andWhere($qb->expr()->eq('principal_type', $qb->createNamedParameter($filters["principalType"], IQueryBuilder::PARAM_INT)));
+        }
+		
+		return $this->findEntities($qb);
+	}
+
+	public function exists(int $organizationFolderId, int $principalType, string $principalId): bool {
+		/* @var $qb IQueryBuilder */
+		$qb = $this->db->getQueryBuilder();
+
+		$qb->select($qb->createFunction('COUNT(1)'))
+			->from(self::ORGANIZATIONFOLDER_MEMBERS_TABLE)
+			->where($qb->expr()->eq('organization_folder_id', $qb->createNamedParameter($organizationFolderId, IQueryBuilder::PARAM_INT)))
+			->andWhere($qb->expr()->eq('principal_type', $qb->createNamedParameter($principalType, IQueryBuilder::PARAM_INT)))
+			->andWhere($qb->expr()->eq('principal_id', $qb->createNamedParameter($principalId)));
+
+		return $qb->executeQuery()->fetch()["COUNT(1)"] === 1;
+	}
+}
\ No newline at end of file
diff --git a/lib/Enum/OrganizationFolderMemberPermissionLevel.php b/lib/Enum/OrganizationFolderMemberPermissionLevel.php
new file mode 100644
index 0000000..67ca95a
--- /dev/null
+++ b/lib/Enum/OrganizationFolderMemberPermissionLevel.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace OCA\OrganizationFolders\Enum;
+
+enum OrganizationFolderMemberPermissionLevel: int {
+    use FromNameEnum;
+    
+    case MEMBER = 1;
+    case MANAGER = 2;
+    case ADMIN = 3;
+}
diff --git a/lib/Errors/OrganizationFolderMemberNotFound.php b/lib/Errors/OrganizationFolderMemberNotFound.php
new file mode 100644
index 0000000..821755c
--- /dev/null
+++ b/lib/Errors/OrganizationFolderMemberNotFound.php
@@ -0,0 +1,9 @@
+<?php
+
+namespace OCA\OrganizationFolders\Errors;
+
+class OrganizationFolderMemberNotFound extends NotFoundException {
+    public function __construct($id) {
+		parent::__construct(\OCA\OrganizationFolders\Db\OrganizationFolderMember::class, ["id" => $id]);
+	}
+}
\ No newline at end of file
diff --git a/lib/Service/OrganizationFolderMemberService.php b/lib/Service/OrganizationFolderMemberService.php
new file mode 100644
index 0000000..1401bc1
--- /dev/null
+++ b/lib/Service/OrganizationFolderMemberService.php
@@ -0,0 +1,129 @@
+<?php
+
+namespace OCA\OrganizationFolders\Service;
+
+use Exception;
+
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\AppFramework\Db\MultipleObjectsReturnedException;
+
+use OCA\OrganizationFolders\Errors\OrganizationFolderMemberNotFound;
+
+use OCA\OrganizationFolders\Db\OrganizationFolderMember;
+use OCA\OrganizationFolders\Db\OrganizationFolderMemberMapper;
+use OCA\OrganizationFolders\Enum\OrganizationFolderMemberPermissionLevel;
+use OCA\OrganizationFolders\Enum\PrincipalType;
+use OCA\OrganizationFolders\Model\Principal;
+
+class OrganizationFolderMemberService {
+	public function __construct(
+        protected OrganizationFolderMemberMapper $mapper,
+		protected OrganizationFolderService $organizationFolderService,
+    ) {
+	}
+
+	/**
+	 * @param int $organizationFolderId
+     * @param array{permissionLevel: OrganizationFolderMemberPermissionLevel, principalType: PrincipalType} $filters
+	 * @return array
+	 * @psalm-return OrganizationFolderMember[]
+	 */
+	public function findAll(int $organizationFolderId, $filters = []): array {
+        $mapperFilters = [
+            "permissionLevel" => $filters['permissionLevel']?->value ?: null,
+            "principalType" => $filters['principalType']?->value ?: null,
+        ];
+
+		return $this->mapper->findAll($organizationFolderId, $mapperFilters);
+	}
+
+    /**
+    * @throws OrganizationFolderMemberNotFound
+    */
+
+	private function handleException(Exception $e): void {
+		if ($e instanceof DoesNotExistException ||
+			$e instanceof MultipleObjectsReturnedException) {
+			throw new OrganizationFolderMemberNotFound($e->getMessage());
+		} else {
+			throw $e;
+		}
+	}
+
+    /** 
+     * @param int $id
+     * @psalm-param int $id
+     * @throws OrganizationFolderMemberNotFound
+     */
+	public function find(int $id): OrganizationFolderMember {
+		try {
+			return $this->mapper->find($id);
+		} catch (Exception $e) {
+			$this->handleException($e);
+		}
+	}
+
+	public function create(
+		int $organizationFolderId,
+		OrganizationFolderMemberPermissionLevel $permissionLevel,
+		Principal $principal,
+	): OrganizationFolderMember {
+		$organizationFolder = $this->organizationFolderService->find($organizationFolderId);
+
+		$member = new OrganizationFolderMember();
+
+		$member->setOrganizationFolderId($organizationFolder->getId());
+		$member->setPermissionLevel($permissionLevel->value);
+		$member->setPrincipal($principal);
+
+        $creationTime = time();
+        $member->setCreatedTimestamp($creationTime);
+        $member->setLastUpdatedTimestamp($creationTime);
+
+		$member = $this->mapper->insert($member);
+
+		$this->organizationFolderService->applyPermissions($organizationFolder->getId());
+
+		return $member;
+	}
+
+	public function update(int $id, ?OrganizationFolderMemberPermissionLevel $permissionLevel = null, ?Principal $principal = null): OrganizationFolderMember {
+		try {
+			$member = $this->mapper->find($id);
+
+            if(isset($permissionLevel)) {
+                $member->setPermissionLevel($permissionLevel->value);
+            }
+
+            if(isset($principal)) {
+				$member->setPrincipal($principal);
+            }
+			
+            if(count($member->getUpdatedFields()) > 0) {
+                $member->setLastUpdatedTimestamp(time());
+
+                $member = $this->mapper->update($member);
+            }
+
+			$this->organizationFolderService->applyPermissions($member->getOrganizationFolderId());
+
+			return $member;
+		} catch (Exception $e) {
+			$this->handleException($e);
+		}
+	}
+
+	public function delete(int $id): OrganizationFolderMember {
+		try {
+			$member = $this->mapper->find($id);
+
+			$this->mapper->delete($member);
+
+			$this->organizationFolderService->applyPermissions($member->getOrganizationFolderId());
+
+			return $member;
+		} catch (Exception $e) {
+			$this->handleException($e);
+		}
+	}
+}
\ No newline at end of file