I ended up calling the projects directly and using their respective namespaces to create the pathToFolder. So rather than cd'ing in and out just create the absolute paths.

import os
import gitlab
from git import Repo

GITLAB_TOKEN = os.getenv('GITLAB_TOKEN')

gl = gitlab.Gitlab(url='https://gitlab.example.priv', private_token=GITLAB_TOKEN)

gitBasePathRelative = "repos/"
gitBasePathRelativeAbsolut = os.path.expanduser("~/" + gitBasePathRelative)
os.makedirs(gitBasePathRelativeAbsolut,exist_ok=True)

for p in gl.projects.list(all=True):
    print("Cloning project " + p.name)
    pathToFolder = p.namespace['name'] + "/" + p.name
    if not os.path.exists(pathToFolder):
        print("\tCreating directory for project " + pathToFolder)
        os.makedirs(pathToFolder)
        Repo.clone_from(p.ssh_url_to_repo, pathToFolder)

Update Dec. 2022, use glab repo clone

glab repo clone -g <group> -a=false -p --paginate

With:

• -p, --preserve-namespace: Clone the repo in a subdirectory based on namespace
• --paginate: Make additional HTTP requests to fetch all pages of projects before cloning. Respects --per-page
• -a, --archived: Limit by archived status. Use with -a=false to exclude archived repositories. Used with --group flag

That does support cloning more than 100 repositories (since MR 1030, and glab v1.24.0, Dec. 2022)

This is for gitlab.com or for a self-managed GitLab instance, provided you set the environment variable GITLAB_URI or GITLAB_HOST: it specifies the URL of the GitLab server if self-managed (eg: https://gitlab.example.com).

Original answer and updates (starting March 2015):

Not really, unless:

• you have a 21st project which references the other 20 as submodules.
  (in which case a clone followed by a git submodule update --init would be enough to get all 20 projects cloned and checked out)

• or you somehow list the projects you have access (GitLab API for projects), and loop on that result to clone each one (meaning that can be scripted, and then executed as "one" command)

Since 2015, Jay Gabez mentions in the comments (August 2019) the tool gabrie30/ghorg

ghorg allows you to quickly clone all of an org's or user's repos into a single directory.

Usage:

$ ghorg clone someorg
$ ghorg clone someuser --clone-type=user --protocol=ssh --branch=develop
$ ghorg clone gitlab-org --scm=gitlab --namespace=gitlab-org/security-products
$ ghorg clone --help

Also (2020): https://github.com/ezbz/gitlabber

usage: gitlabber [-h] [-t token] [-u url] [--debug] [-p]
                [--print-format {json,yaml,tree}] [-i csv] [-x csv]
                [--version]
                [dest]

Gitlabber - clones or pulls entire groups/projects tree from gitlab

It looks like there's not a straightforward solution for HTTPS-based cloning regarding GitLab. Therefore if you want a SSH-based cloning, you should take account these three forthcoming steps:

• Create properly an SSH key using your email used to sign up. I would use the default filename to key for Windows. Don't forget to introduce a password! (tip: you can skip this step if you already have one ssh key here)

   $ ssh-keygen -t rsa -C "[email protected]" -b 4096
  
   Generating public/private rsa key pair.
   Enter file in which to save the key ($PWD/.ssh/id_rsa): [\n]
   Enter passphrase (empty for no passphrase):[your password]
   Enter same passphrase again: [your password]
   Your identification has been saved in $PWD/.ssh/id_rsa.
   Your public key has been saved in $PWD/.ssh/id_rsa.pub.
  

• Copy and paste all content from the recently id_rsa.pub generated into Setting>SSH keys>Key from your GitLab profile.

   # Copy to clipboard
   pbcopy < ~/.ssh/id_rsa.pub
  

• Get locally connected:

   $ ssh -i $PWD/.ssh/id_rsa [email protected]
  
   Enter passphrase for key "$PWD/.ssh/id_rsa": [your password]
   PTY allocation request failed on channel 0
   Welcome to GitLab, you!
   Connection to gitlab.com closed.
  

Finally, clone any private or internal GitLab repository!

$ git clone https://git.metabarcoding.org/obitools/ROBIBarcodes.git

Cloning into 'ROBIBarcodes'...
remote: Counting objects: 69, done.
remote: Compressing objects: 100% (65/65), done.
remote: Total 69 (delta 14), reused 0 (delta 0)
Unpacking objects: 100% (69/69), done.