diff --git a/bootstrap/bootstrap.py b/bootstrap/bootstrap.py
index e15128997..f3759b7d6 100644
--- a/bootstrap/bootstrap.py
+++ b/bootstrap/bootstrap.py
@@ -42,6 +42,7 @@
 import os
 from http.server import SimpleHTTPRequestHandler, HTTPServer
 import multiprocessing
+import re
 import subprocess
 import sys
 import logging
@@ -166,9 +167,11 @@ def run_subprocess(cmd, *args, **kwargs):
                 command=printable_command, code=proc.returncode
             )
         )
+        output = proc.stdout.decode()
         # This produces multi line log output, unfortunately. Not sure how to fix.
         # For now, prioritizing human readability over machine readability.
-        logger.debug(proc.stdout.decode())
+        logger.debug(output)
+        return output
 
 
 def ensure_host_system_can_install_tljh():
@@ -251,6 +254,73 @@ def do_GET(self):
             SimpleHTTPRequestHandler.send_error(self, code=403)
 
 
+def _find_matching_version(all_versions, requested):
+    """
+    Find the latest version that is less than or equal to requested.
+    all_versions must be int-tuples.
+    requested must be an int-tuple or "latest"
+
+    Returns None if no version is found.
+    """
+    sorted_versions = sorted(all_versions, reverse=True)
+    if requested == "latest":
+        return sorted_versions[0]
+    components = len(requested)
+    for v in sorted_versions:
+        if v[:components] == requested:
+            return v
+    return None
+
+
+def _resolve_git_version(version):
+    """
+    Resolve the version argument to a git ref using git ls-remote
+    - If version looks like MAJOR.MINOR.PATCH or a partial tag then fetch all tags
+      and return the most latest tag matching MAJOR.MINOR.PATCH
+      (e.g. version=0.1 -> 0.1.PATCH). This should ignore dev tags
+    - If version='latest' then return the latest release tag
+    - Otherwise assume version is a branch or hash and return it without checking
+    """
+
+    if version != "latest" and not re.match(r"\d+(\.\d+)?(\.\d+)?$", version):
+        return version
+
+    all_versions = set()
+    out = run_subprocess(
+        [
+            "git",
+            "ls-remote",
+            "--tags",
+            "--refs",
+            "https://github.com/jupyterhub/the-littlest-jupyterhub.git",
+        ]
+    )
+
+    for line in out.splitlines():
+        m = re.match(r"(?P<sha>[a-f0-9]+)\s+refs/tags/(?P<tag>[\S]+)$", line)
+        if not m:
+            raise Exception("Unexpected git ls-remote output: {}".format(line))
+        tag = m.group("tag")
+        if tag == version:
+            return tag
+        if re.match(r"\d+\.\d+\.\d+$", tag):
+            all_versions.add(tuple(int(v) for v in tag.split(".")))
+
+    if not all_versions:
+        raise Exception("No MAJOR.MINOR.PATCH git tags found")
+
+    if version == "latest":
+        requested = "latest"
+    else:
+        requested = tuple(int(v) for v in version.split("."))
+    found = _find_matching_version(all_versions, requested)
+    if not found:
+        raise Exception(
+            "No version matching {} found {}".format(version, sorted(all_versions))
+        )
+    return ".".join(str(f) for f in found)
+
+
 def main():
     """
     This bootstrap script intercepts some command line flags, everything else is
@@ -265,7 +335,7 @@ def main():
     parser = ArgumentParser()
     parser.add_argument("--show-progress-page", action="store_true")
     parser.add_argument(
-        "--version", default="main", help="TLJH version (Git reference)"
+        "--version", default="main", help="TLJH version or Git reference"
     )
     args, tljh_installer_flags = parser.parse_known_args()
 
@@ -378,11 +448,13 @@ def serve_forever(server):
     if os.environ.get("TLJH_BOOTSTRAP_DEV", "no") == "yes":
         logger.info("Selected TLJH_BOOTSTRAP_DEV=yes...")
         tljh_install_cmd.append("--editable")
+    version = _resolve_git_version(args.version)
+
     tljh_install_cmd.append(
         os.environ.get(
             "TLJH_BOOTSTRAP_PIP_SPEC",
-            "git+https://github.com/jupyterhub/the-littlest-jupyterhub.git@{version}".format(
-                version=args.version
+            "git+https://github.com/jupyterhub/the-littlest-jupyterhub.git@{}".format(
+                version
             ),
         )
     )
diff --git a/mock-tests/test_bootstrap.py b/mock-tests/test_bootstrap.py
new file mode 100644
index 000000000..ba4b3f56c
--- /dev/null
+++ b/mock-tests/test_bootstrap.py
@@ -0,0 +1,123 @@
+# Unit test some functions from bootstrap.py
+# Since bootstrap.py isn't part of the package, it's not automatically importable
+import os
+import sys
+
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
+
+from bootstrap import bootstrap
+import pytest
+
+
+@pytest.mark.parametrize(
+    "requested,expected",
+    [
+        ((1,), (1, 1, 0)),
+        ((1, 0), (1, 0, 1)),
+        ((1, 2), None),
+        ((2, 0, 0), (2, 0, 0)),
+        ("latest", (2, 0, 1)),
+    ],
+)
+def test_find_matching_version(requested, expected):
+    all_versions = [
+        (0, 0, 1),
+        (1, 0, 0),
+        (1, 0, 1),
+        (1, 1, 0),
+        (2, 0, 0),
+        (2, 0, 1),
+    ]
+    r = bootstrap._find_matching_version(all_versions, requested)
+    assert r == expected
+
+
+# git ls-remote --tags --refs https://github.com/jupyterhub/jupyterhub.git
+mock_git_ls_remote = """\
+c345aa658eb482b8102b51f6ec3f0fc667b60520	refs/tags/0.1.0
+e2cbc2fb41c04cfe416b19e83f36ea67b1a4e693	refs/tags/0.2.0
+7fd56fe943bf0038cb14e7aa2af5a3e5ad929d47	refs/tags/0.3.0
+89cf4c60a905b4093ba7584c4561073a9faa0d3d	refs/tags/0.4.0
+bd08efc4a5485a9ecd17882e9bfcab9486d9956a	refs/tags/0.4.1
+19c77d0c7016c08a4a0e883446114a430a551882	refs/tags/0.5.0
+b4621d354b6bbc865373b7c033f29c6872237780	refs/tags/0.6.0
+ed38f08daf4d5cf84f04b2d96327681221c579dd	refs/tags/0.6.1
+d5cf9657f2ca16df080e2be21da792288e9f4f99	refs/tags/0.7.0
+2cdb4be46a0eb291850fc706cfe044873889a9bc	refs/tags/0.7.1
+e4dd65d2611e3c85fe486c561fc0efe9ca720042	refs/tags/0.7.2
+4179668e49ceedb805cb1a38dc5a70e6a21fa685	refs/tags/0.8.0
+9bab206eb96c6726ac936cf5da3f61eb9c9aa519	refs/tags/0.8.0b1
+5f2c6d25fefcbe91d86945f530e6533822449c46	refs/tags/0.8.0b2
+0d720103c5207d008947580b7b453e1eb0e7594a	refs/tags/0.8.0b3
+a2458ffa402fa2d2905c558100c673e98789a8a8	refs/tags/0.8.0b4
+b9e2838a4d9b35a9ad7c3353e62ab006b4ec10a4	refs/tags/0.8.0b5
+a62fc1bc1c9b2408713511cb56e7751403ed5503	refs/tags/0.8.0rc1
+a77ca08e3e25c14552e246e8ad3ca65a354ba192	refs/tags/0.8.0rc2
+6eef64842a7d7939b3f1986558849d1977a0e121	refs/tags/0.8.1
+de46a16029b7ae217293e7e64e14a9c2e06e5e60	refs/tags/0.9.0
+9f612b52187db878f529458e304bd519fda82e42	refs/tags/0.9.0b1
+ec4b038b93495eb769007a0d3d56e6d6a5ff000c	refs/tags/0.9.0b2
+ea8a30b1a5b189b2f2f0dbfdb22f83427d1c9163	refs/tags/0.9.0b3
+99c155a61a1d95a3a8ca41ebb684cdedc1fb170f	refs/tags/0.9.0rc1
+1aeebd4e4937ea5185ce02f693f94272c30f4ebd	refs/tags/0.9.1
+01b3601a12b52259b541b48eaa7a7afb3f7d988c	refs/tags/0.9.2
+70ddc22e071bb7797528831d25c567f6f4920c67	refs/tags/0.9.3
+7ecb093163a453ae2edfa6bc8bf1f7cfc2320627	refs/tags/0.9.4
+3e83bc440b8d5abdc0a4336978bd542435402f77	refs/tags/0.9.5
+cc07c706931c78f46367db9c0c20e6ed9f0f6f85	refs/tags/0.9.6
+4e24276d40ad83fd113c7c2f1f8619a9ba3af0d8	refs/tags/1.0.0
+582162c760e81995f4f5405e9c8908d2a76f4abf	refs/tags/1.0.0b1
+1193f6a74c38b36594f6f57c786fa923a2747150	refs/tags/1.0.0b2
+512dae6cd8a846dd490d77d21fd4e13f59c38961	refs/tags/1.1.0
+a420c55391273852332ef5f454a0a3b9e0e5b71f	refs/tags/1.1.0b1
+317f0efaf25eb7cb2de4503817cf20937ce110bd	refs/tags/1.2.0
+f66e5d35b5f89a28f6328c91801a8f99e0855a8e	refs/tags/1.2.0b1
+27e1196471729cf6f25fd3786286797e32de973a	refs/tags/1.2.1
+af0c1ed932d00fa26ac91f066a5a9eafb49b7cb1	refs/tags/1.2.2
+3794abfbdda0a92237f4c31985420691da70da36	refs/tags/1.3.0
+e22ab5dc93dd8e724b828a0880032f6b5dc00231	refs/tags/1.4.0
+0656586b75b30091583c0573b3d272cb3add24d2	refs/tags/1.4.1
+5744ce73bcf0014cc3de6c946f12027448b136da	refs/tags/1.4.2
+c6fb64d8f30686c2c2667b69b53402d506a3bac5	refs/tags/1.5.0
+4ceb906435dbd4cf800b0480d413303f056e4900	refs/tags/2.0.0
+61233698dfb353c703ea2e085312b9066ea2e92e	refs/tags/2.0.0b1
+fe61c932409550dc352abf68bd6aaaa8871ac81f	refs/tags/2.0.0b2
+a79c5c5a6bfe553af277f2835419d65b98ae0cb9	refs/tags/2.0.0b3
+fa1098a998561321de29c6147235032fd6b0c3f5	refs/tags/2.0.0rc1
+75b115c356983c138c2d8d92cb45f068ad3d9c9d	refs/tags/2.0.0rc2
+ed8e25ef3f471d60b671f2a1cf2db17581c778a2	refs/tags/2.0.0rc3
+4083307b3f37039075862034963ed42a459b1bdb	refs/tags/2.0.0rc4
+baf1f36dbfe8d8264b3914650b4db6daed843389	refs/tags/2.0.0rc5
+12961be3b13a10617d8f95f333da2bb67390a2c7	refs/tags/2.0.1
+e40df3f1a5e284926f5c9ce66a1e57a814bb98f8	refs/tags/2.0.2
+11d40c13860bd02816ad724979ad2e08b8bd103a	refs/tags/2.1.0
+bde6b66287e3d157f2577bcaf2e986af020139f4	refs/tags/2.1.1
+29f51794db562ecc4c7653525193d6e210151fdb	refs/tags/2.2.0
+8cbafd25425b7eaf2fdc46e183cee437c09b53c1	refs/tags/2.2.1
+1eada986101f2385ee7498395a799f28bcd167e8	refs/tags/2.2.2
+1bb0ec38ae4c5e4e5c8b6cc3b89b7b20ea8bd400	refs/tags/2.3.0
+69f926706be03505f9b9e30a5ad2d4f8c9f9d48d	refs/tags/2.3.1
+"""
+
+
+@pytest.mark.parametrize(
+    "requested,expected",
+    [
+        ("1", "1.5.0"),
+        ("1.0", "1.0.0"),
+        ("1.2", "1.2.2"),
+        # ("1.100", None),
+        ("2.0.0", "2.0.0"),
+        ("random-branch", "random-branch"),
+        ("1234567890abcdef", "1234567890abcdef"),
+        ("2.0.0rc4", "2.0.0rc4"),
+        ("latest", "2.3.1"),
+    ],
+)
+def test_resolve_git_version(monkeypatch, requested, expected):
+    def mock_run_subprocess(*args, **kwargs):
+        return mock_git_ls_remote
+
+    monkeypatch.setattr(bootstrap, "run_subprocess", mock_run_subprocess)
+
+    assert bootstrap._resolve_git_version(requested) == expected