diff --git a/client_document_add_file_relation_modal.php b/client_document_add_file_relation_modal.php
new file mode 100644
index 00000000..37a7b13f
--- /dev/null
+++ b/client_document_add_file_relation_modal.php
@@ -0,0 +1,48 @@
+<div class="modal" id="associateFileToDocumentModal" tabindex="-1">
+    <div class="modal-dialog">
+        <div class="modal-content bg-dark">
+            <div class="modal-header">
+                <h5 class="modal-title"><i class="fa fa-fw fa-paperclip mr-2"></i>Associate File to <strong><?php echo $document_name; ?></strong></h5>
+                <button type="button" class="close text-white" data-dismiss="modal">
+                    <span>&times;</span>
+                </button>
+            </div>
+            <form action="post.php" method="post" autocomplete="off">
+                <input type="hidden" name="client_id" value="<?php echo $client_id; ?>">
+                <input type="hidden" name="document_id" value="<?php echo $document_id; ?>">
+                <div class="modal-body bg-white">
+
+                    <div class="form-group">
+                        <div class="input-group">
+                            <div class="input-group-prepend">
+                                <span class="input-group-text"><i class="fa fa-fw fa-paperclip"></i></span>
+                            </div>
+                            <select class="form-control select2" name="file_id">
+                                <option value="">- Select a File -</option>
+                                <?php
+                                $sql_files_select = mysqli_query($mysqli, "SELECT * FROM files 
+                                    LEFT JOIN folders ON folder_id = file_folder_id
+                                    WHERE file_client_id = $client_id ORDER BY folder_name ASC, file_name ASC");
+                                while ($row = mysqli_fetch_array($sql_files_select)) {
+                                    $file_id = intval($row['file_id']);
+                                    $file_name = nullable_htmlentities($row['file_name']);
+                                    $folder_name = nullable_htmlentities($row['folder_name']);
+
+                                    ?>
+                                    <option value="<?php echo $file_id ?>"><?php echo "$folder_name/$file_name"; ?></option>
+                                    <?php
+                                }
+                                ?>
+
+                            </select>
+                        </div>
+                    </div>
+                </div>
+                <div class="modal-footer bg-white">
+                    <button type="submit" name="associate_file_to_document" class="btn btn-primary text-bold"><i class="fa fa-check mr-2"></i>Associate</button>
+                    <button type="button" class="btn btn-light" data-dismiss="modal"><i class="fa fa-times mr-2"></i>Cancel</button>
+                </div>
+            </form>
+        </div>
+    </div>
+</div>
diff --git a/client_document_associate_file_modal.php b/client_document_associate_file_modal.php
new file mode 100644
index 00000000..37a7b13f
--- /dev/null
+++ b/client_document_associate_file_modal.php
@@ -0,0 +1,48 @@
+<div class="modal" id="associateFileToDocumentModal" tabindex="-1">
+    <div class="modal-dialog">
+        <div class="modal-content bg-dark">
+            <div class="modal-header">
+                <h5 class="modal-title"><i class="fa fa-fw fa-paperclip mr-2"></i>Associate File to <strong><?php echo $document_name; ?></strong></h5>
+                <button type="button" class="close text-white" data-dismiss="modal">
+                    <span>&times;</span>
+                </button>
+            </div>
+            <form action="post.php" method="post" autocomplete="off">
+                <input type="hidden" name="client_id" value="<?php echo $client_id; ?>">
+                <input type="hidden" name="document_id" value="<?php echo $document_id; ?>">
+                <div class="modal-body bg-white">
+
+                    <div class="form-group">
+                        <div class="input-group">
+                            <div class="input-group-prepend">
+                                <span class="input-group-text"><i class="fa fa-fw fa-paperclip"></i></span>
+                            </div>
+                            <select class="form-control select2" name="file_id">
+                                <option value="">- Select a File -</option>
+                                <?php
+                                $sql_files_select = mysqli_query($mysqli, "SELECT * FROM files 
+                                    LEFT JOIN folders ON folder_id = file_folder_id
+                                    WHERE file_client_id = $client_id ORDER BY folder_name ASC, file_name ASC");
+                                while ($row = mysqli_fetch_array($sql_files_select)) {
+                                    $file_id = intval($row['file_id']);
+                                    $file_name = nullable_htmlentities($row['file_name']);
+                                    $folder_name = nullable_htmlentities($row['folder_name']);
+
+                                    ?>
+                                    <option value="<?php echo $file_id ?>"><?php echo "$folder_name/$file_name"; ?></option>
+                                    <?php
+                                }
+                                ?>
+
+                            </select>
+                        </div>
+                    </div>
+                </div>
+                <div class="modal-footer bg-white">
+                    <button type="submit" name="associate_file_to_document" class="btn btn-primary text-bold"><i class="fa fa-check mr-2"></i>Associate</button>
+                    <button type="button" class="btn btn-light" data-dismiss="modal"><i class="fa fa-times mr-2"></i>Cancel</button>
+                </div>
+            </form>
+        </div>
+    </div>
+</div>
diff --git a/client_document_associate_vendor_modal.php b/client_document_associate_vendor_modal.php
new file mode 100644
index 00000000..56aa2cb7
--- /dev/null
+++ b/client_document_associate_vendor_modal.php
@@ -0,0 +1,58 @@
+<div class="modal" id="associateVendorToDocumentModal" tabindex="-1">
+    <div class="modal-dialog">
+        <div class="modal-content bg-dark">
+            <div class="modal-header">
+                <h5 class="modal-title"><i class="fa fa-fw fa-building mr-2"></i>Associate Vendor to <strong><?php echo $document_name; ?></strong></h5>
+                <button type="button" class="close text-white" data-dismiss="modal">
+                    <span>&times;</span>
+                </button>
+            </div>
+            <form action="post.php" method="post" autocomplete="off">
+                <input type="hidden" name="client_id" value="<?php echo $client_id; ?>">
+                <input type="hidden" name="document_id" value="<?php echo $document_id; ?>">
+                <div class="modal-body bg-white">
+
+                    <div class="form-group">
+                        <div class="input-group">
+                            <div class="input-group-prepend">
+                                <span class="input-group-text"><i class="fa fa-fw fa-building"></i></span>
+                            </div>
+                            <select class="form-control select2" name="vendor_id">
+                                <option value="">- Select a Vendor -</option>
+                                <?php
+                                // Check if there are any associated vendors
+                                if (!empty($associated_vendors)) {
+                                    $excluded_vendor_ids = implode(",", $associated_vendors);
+                                    $exclude_condition = "AND vendor_id NOT IN ($excluded_vendor_ids)";
+                                } else {
+                                    $exclude_condition = "";  // No condition if there are no displayed vendors
+                                }
+
+                                $sql_vendors_select = mysqli_query($mysqli, "SELECT * FROM vendors 
+                                    WHERE vendor_client_id = $client_id 
+                                    AND vendor_archived_at IS NULL
+                                    $exclude_condition
+                                    ORDER BY vendor_name ASC"
+                                );
+                                while ($row = mysqli_fetch_array($sql_vendors_select)) {
+                                    $vendor_id = intval($row['vendor_id']);
+                                    $vendor_name = nullable_htmlentities($row['vendor_name']);
+
+                                    ?>
+                                    <option value="<?php echo $vendor_id ?>"><?php echo $vendor_name; ?></option>
+                                    <?php
+                                }
+                                ?>
+
+                            </select>
+                        </div>
+                    </div>
+                </div>
+                <div class="modal-footer bg-white">
+                    <button type="submit" name="associate_vendor_to_document" class="btn btn-primary text-bold"><i class="fa fa-check mr-2"></i>Associate</button>
+                    <button type="button" class="btn btn-light" data-dismiss="modal"><i class="fa fa-times mr-2"></i>Cancel</button>
+                </div>
+            </form>
+        </div>
+    </div>
+</div>
diff --git a/client_document_details.php b/client_document_details.php
index 0623b990..592cc223 100644
--- a/client_document_details.php
+++ b/client_document_details.php
@@ -63,7 +63,7 @@ $document_folder_id = intval($row['document_folder_id']);
         <h5>Related</h5>
         <h6>
           <i class="fas fa-fw fa-paperclip text-secondary mr-2"></i>Files
-          <button type="button" class="btn btn-link btn-sm">
+          <button type="button" class="btn btn-link btn-sm" data-toggle="modal" data-target="#associateFileToDocumentModal">
             <i class="fas fa-fw fa-plus"></i>
           </button>
         </h6>
@@ -93,11 +93,37 @@ $document_folder_id = intval($row['document_folder_id']);
         </h6>
         <h6>
           <i class="fas fa-fw fa-building text-secondary mr-2"></i>Vendors
-          <button type="button" class="btn btn-link btn-sm">
+          <button type="button" class="btn btn-link btn-sm" data-toggle="modal" data-target="#associateVendorToDocumentModal">
             <i class="fas fa-fw fa-plus"></i>
           </button>
         </h6>
+        <ul>
+          <?php
+          $sql_vendors = mysqli_query($mysqli, "SELECT * FROM vendors, vendor_documents
+            WHERE vendors.vendor_id = vendor_documents.vendor_id 
+            AND vendor_documents.document_id = $document_id
+            ORDER BY vendor_name ASC"
+          );
+          
+          $associated_vendors = array();
 
+          while ($row = mysqli_fetch_array($sql_vendors)) {
+            $vendor_id = intval($row['vendor_id']);
+            $vendor_name = nullable_htmlentities($row['vendor_name']);
+
+            $associated_vendors[] = $vendor_id;
+
+            ?>
+            <li>
+              <?php echo $vendor_name; ?> 
+              <a href="post.php?unassociate_vendor_from_document&vendor_id=<?php echo $vendor_id; ?>&document_id=<?php echo $document_id; ?>">
+                <i class="fas fa-fw fa-times text-secondary ml-2"></i>
+              </a>
+            </li>
+          <?php
+          }
+          ?>
+      </ul>
       </div>
     </div>
 
@@ -108,6 +134,8 @@ $document_folder_id = intval($row['document_folder_id']);
 <?php
 
 require_once("client_document_edit_modal.php");
+require_once("client_document_associate_file_modal.php");
+require_once("client_document_associate_vendor_modal.php");
 require_once("share_modal.php");
 require_once("footer.php");
 
diff --git a/post/document.php b/post/document.php
index 8186fd42..f4efa694 100644
--- a/post/document.php
+++ b/post/document.php
@@ -132,6 +132,43 @@ if (isset($_POST['move_document'])) {
 
 }
 
+if (isset($_POST['associate_vendor_to_document'])) {
+
+    validateTechRole();
+
+    $client_id = intval($_POST['client_id']);
+    $document_id = intval($_POST['document_id']);
+    $vendor_id = intval($_POST['vendor_id']);
+
+    // Document add query
+    mysqli_query($mysqli,"INSERT INTO vendor_documents SET vendor_id = $vendor_id, document_id = $document_id");
+
+    // Logging
+    mysqli_query($mysqli,"INSERT INTO logs SET log_type = 'Document', log_action = 'Create', log_description = 'Created Document Vendor Relation', log_ip = '$session_ip', log_user_agent = '$session_user_agent', log_client_id = $client_id, log_user_id = $session_user_id");
+
+    $_SESSION['alert_message'] = "Vendor associated with Document";
+
+    header("Location: " . $_SERVER["HTTP_REFERER"]);
+
+}
+
+if (isset($_GET['unassociate_vendor_from_document'])) {
+
+    validateTechRole();
+    $vendor_id = intval($_GET['vendor_id']);
+    $document_id = intval($_GET['document_id']);
+
+    mysqli_query($mysqli,"DELETE FROM vendor_documents WHERE vendor_id = $vendor_id AND document_id = $document_id");
+
+    //Logging
+    mysqli_query($mysqli,"INSERT INTO logs SET log_type = 'Document', log_action = 'Delete', log_description = 'Document Vendor relationship removed', log_ip = '$session_ip', log_user_agent = '$session_user_agent', log_user_id = $session_user_id");
+
+    $_SESSION['alert_message'] = "Vendor has been unassciated";
+
+    header("Location: " . $_SERVER["HTTP_REFERER"]);
+
+}
+
 if (isset($_POST['edit_document_template'])) {
 
     validateTechRole();