diff --git a/swh/core/statsd.py b/swh/core/statsd.py
--- a/swh/core/statsd.py
+++ b/swh/core/statsd.py
@@ -57,6 +57,7 @@
 import logging
 import os
 from random import random
+import re
 import socket
 import threading
 from time import monotonic
@@ -221,6 +222,14 @@
                 )
                 continue
             k, v = tag.split(":", 1)
+
+            # look for a possible env var substitution, using $NAME or ${NAME} format
+            m = re.match(r"^[$]([{])?(?P<envvar>\w+)(?(1)[}]|)$", v)
+            if m:
+                envvar = m.group("envvar")
+                if envvar in os.environ:
+                    v = os.environ[envvar]
+
             self.constant_tags[k] = v
 
         if constant_tags:
diff --git a/swh/core/tests/test_statsd.py b/swh/core/tests/test_statsd.py
--- a/swh/core/tests/test_statsd.py
+++ b/swh/core/tests/test_statsd.py
@@ -428,6 +428,21 @@
     assert statsd.socket.recv() == "gt:123.4|g|#age:45,country:china"
 
 
+def test_tags_from_environment_with_substitution(monkeypatch):
+    monkeypatch.setenv("HOSTNAME", "sweethome")
+    monkeypatch.setenv("PORT", "42")
+    monkeypatch.setenv(
+        "STATSD_TAGS", "country:china,age:45,host:$HOSTNAME,port:${PORT}"
+    )
+    statsd = Statsd()
+    statsd._socket = FakeSocket()
+    statsd.gauge("gt", 123.4)
+    assert (
+        statsd.socket.recv()
+        == "gt:123.4|g|#age:45,country:china,host:sweethome,port:42"
+    )
+
+
 def test_tags_from_environment_and_constant(monkeypatch):
     monkeypatch.setenv("STATSD_TAGS", "country:china,age:45")
     statsd = Statsd(constant_tags={"country": "canada"})