diff --git a/client/src/validations/regExps.js b/client/src/validations/regExps.js
index 6ff068693..437c881ec 100644
--- a/client/src/validations/regExps.js
+++ b/client/src/validations/regExps.js
@@ -27,7 +27,7 @@ export const validateSSHKey = sshKey => {
 
 
 const shortNameRegexp = /^[^a-z]*|[^a-z_0-9]+/gi
-const tagNameRegexp   = /^[^a-z]*|[^a-z_0-9-]+/gi
+const tagNameRegexp   = /^[^a-z0-9]*|[^a-z_0-9-]+/gi
 
 export const sanitizeShortName = shortName => {
     return shortName ? shortName.replace(shortNameRegexp, "").substring(0, 16).toLowerCase() : shortName;
diff --git a/server/db/defaults.py b/server/db/defaults.py
index d2a66c796..69a403154 100644
--- a/server/db/defaults.py
+++ b/server/db/defaults.py
@@ -65,7 +65,7 @@ def valid_uri_attributes(data, uri_attributes):
     return True
 
 
-tag_re = re.compile(r"^[a-z][a-z_0-9-]+$")
+tag_re = re.compile(r"^[a-z0-9][a-z_0-9-]+$")
 
 
 def valid_tag_label(tag_value: Optional[str]) -> bool: