diff --git a/bukkit/src/main/resources/config.yml b/bukkit/src/main/resources/config.yml
index d8978f40..6d3b2306 100644
--- a/bukkit/src/main/resources/config.yml
+++ b/bukkit/src/main/resources/config.yml
@@ -70,6 +70,12 @@ use-server-uuids: true
 # in the LuckPerms cache.
 use-server-uuid-cache: false
 
+# If set to true, LuckPerms will allow usernames with non alphanumeric characters.
+#
+# Note that due to the design of the storage implementation, usernames must still be
+# 16 characters or less.
+allow-invalid-usernames: false
+
 # If LuckPerms should produce extra logging output when it handles logins.
 # Useful if you're having issues with UUID forwarding or data not being loaded.
 debug-logins: false
diff --git a/bungee/src/main/resources/config.yml b/bungee/src/main/resources/config.yml
index 8122eea3..a6158c0a 100644
--- a/bungee/src/main/resources/config.yml
+++ b/bungee/src/main/resources/config.yml
@@ -73,6 +73,12 @@ use-server-uuids: true
 # try to find a uuid for a username using RedisBungee, if installed.
 use-server-uuid-cache: false
 
+# If set to true, LuckPerms will allow usernames with non alphanumeric characters.
+#
+# Note that due to the design of the storage implementation, usernames must still be
+# 16 characters or less.
+allow-invalid-usernames: false
+
 # If LuckPerms should produce extra logging output when it handles logins.
 # Useful if you're having issues with UUID forwarding or data not being loaded.
 debug-logins: false
diff --git a/common/src/main/java/me/lucko/luckperms/common/commands/impl/log/LogRecent.java b/common/src/main/java/me/lucko/luckperms/common/commands/impl/log/LogRecent.java
index 0064d0ed..f6a6803a 100644
--- a/common/src/main/java/me/lucko/luckperms/common/commands/impl/log/LogRecent.java
+++ b/common/src/main/java/me/lucko/luckperms/common/commands/impl/log/LogRecent.java
@@ -73,9 +73,16 @@ public class LogRecent extends SubCommand<Log> {
         final String target = args.get(0);
         UUID uuid = Util.parseUuid(target.toLowerCase());
         if (uuid == null) {
-            if (!DataConstraints.PLAYER_USERNAME_TEST.test(target)) {
-                Message.USER_INVALID_ENTRY.send(sender, target);
-                return CommandResult.INVALID_ARGS;
+            if (!plugin.getConfiguration().get(ConfigKeys.ALLOW_INVALID_USERNAMES)) {
+                if (!DataConstraints.PLAYER_USERNAME_TEST.test(target)) {
+                    Message.USER_INVALID_ENTRY.send(sender, target);
+                    return CommandResult.INVALID_ARGS;
+                }
+            } else {
+                if (!DataConstraints.PLAYER_USERNAME_TEST_LENIENT.test(target)) {
+                    Message.USER_INVALID_ENTRY.send(sender, target);
+                    return CommandResult.INVALID_ARGS;
+                }
             }
 
             uuid = plugin.getStorage().getUUID(target.toLowerCase()).join();
diff --git a/common/src/main/java/me/lucko/luckperms/common/commands/impl/log/LogUserHistory.java b/common/src/main/java/me/lucko/luckperms/common/commands/impl/log/LogUserHistory.java
index 34775962..44345bd4 100644
--- a/common/src/main/java/me/lucko/luckperms/common/commands/impl/log/LogUserHistory.java
+++ b/common/src/main/java/me/lucko/luckperms/common/commands/impl/log/LogUserHistory.java
@@ -68,22 +68,29 @@ public class LogUserHistory extends SubCommand<Log> {
 
         UUID uuid = Util.parseUuid(target.toLowerCase());
         if (uuid == null) {
-            if (!DataConstraints.PLAYER_USERNAME_TEST.test(target)) {
-                Message.USER_INVALID_ENTRY.send(sender, target);
-                return null;
+            if (!plugin.getConfiguration().get(ConfigKeys.ALLOW_INVALID_USERNAMES)) {
+                if (!DataConstraints.PLAYER_USERNAME_TEST.test(target)) {
+                    Message.USER_INVALID_ENTRY.send(sender, target);
+                    return CommandResult.INVALID_ARGS;
+                }
+            } else {
+                if (!DataConstraints.PLAYER_USERNAME_TEST_LENIENT.test(target)) {
+                    Message.USER_INVALID_ENTRY.send(sender, target);
+                    return CommandResult.INVALID_ARGS;
+                }
             }
 
             uuid = plugin.getStorage().getUUID(target.toLowerCase()).join();
             if (uuid == null) {
                 if (!plugin.getConfiguration().get(ConfigKeys.USE_SERVER_UUID_CACHE)) {
                     Message.USER_NOT_FOUND.send(sender, target);
-                    return null;
+                    return CommandResult.INVALID_ARGS;
                 }
 
                 uuid = plugin.lookupUuid(target).orElse(null);
                 if (uuid == null) {
                     Message.USER_NOT_FOUND.send(sender, target);
-                    return null;
+                    return CommandResult.INVALID_ARGS;
                 }
             }
         }
diff --git a/common/src/main/java/me/lucko/luckperms/common/commands/impl/user/UserMainCommand.java b/common/src/main/java/me/lucko/luckperms/common/commands/impl/user/UserMainCommand.java
index 2751edd6..abf4238c 100644
--- a/common/src/main/java/me/lucko/luckperms/common/commands/impl/user/UserMainCommand.java
+++ b/common/src/main/java/me/lucko/luckperms/common/commands/impl/user/UserMainCommand.java
@@ -83,9 +83,16 @@ public class UserMainCommand extends MainCommand<User, UserIdentifier> {
     protected UserIdentifier parseTarget(String target, LuckPermsPlugin plugin, Sender sender) {
         UUID uuid = Util.parseUuid(target.toLowerCase());
         if (uuid == null) {
-            if (!DataConstraints.PLAYER_USERNAME_TEST.test(target)) {
-                Message.USER_INVALID_ENTRY.send(sender, target);
-                return null;
+            if (!plugin.getConfiguration().get(ConfigKeys.ALLOW_INVALID_USERNAMES)) {
+                if (!DataConstraints.PLAYER_USERNAME_TEST.test(target)) {
+                    Message.USER_INVALID_ENTRY.send(sender, target);
+                    return null;
+                }
+            } else {
+                if (!DataConstraints.PLAYER_USERNAME_TEST_LENIENT.test(target)) {
+                    Message.USER_INVALID_ENTRY.send(sender, target);
+                    return null;
+                }
             }
 
             uuid = plugin.getStorage().getUUID(target.toLowerCase()).join();
diff --git a/common/src/main/java/me/lucko/luckperms/common/config/ConfigKeys.java b/common/src/main/java/me/lucko/luckperms/common/config/ConfigKeys.java
index e5985c66..b0a9668a 100644
--- a/common/src/main/java/me/lucko/luckperms/common/config/ConfigKeys.java
+++ b/common/src/main/java/me/lucko/luckperms/common/config/ConfigKeys.java
@@ -122,6 +122,11 @@ public class ConfigKeys {
      */
     public static final ConfigKey<Boolean> USE_SERVER_UUID_CACHE = BooleanKey.of("use-server-uuid-cache", false);
 
+    /**
+     * If LuckPerms should allow usernames with non alphanumeric characters.
+     */
+    public static final ConfigKey<Boolean> ALLOW_INVALID_USERNAMES = BooleanKey.of("allow-invalid-usernames", false);
+
     /**
      * If LuckPerms should produce extra logging output when it handles logins.
      */
diff --git a/common/src/main/java/me/lucko/luckperms/common/constants/DataConstraints.java b/common/src/main/java/me/lucko/luckperms/common/constants/DataConstraints.java
index af831439..354aede0 100644
--- a/common/src/main/java/me/lucko/luckperms/common/constants/DataConstraints.java
+++ b/common/src/main/java/me/lucko/luckperms/common/constants/DataConstraints.java
@@ -68,6 +68,14 @@ public class DataConstraints {
         return true;
     };
 
+    public static final Predicate<String> PLAYER_USERNAME_TEST_LENIENT = s -> {
+        if (s.length() <= 0 || s.length() > MAX_PLAYER_USERNAME_LENGTH) {
+            return false;
+        }
+
+        return true;
+    };
+
     public static final Predicate<String> GROUP_NAME_TEST = s -> {
         if (s.length() <= 0 || s.length() > MAX_GROUP_NAME_LENGTH) {
             return false;
diff --git a/sponge/src/main/resources/luckperms.conf b/sponge/src/main/resources/luckperms.conf
index f1ed8fe2..12a42878 100644
--- a/sponge/src/main/resources/luckperms.conf
+++ b/sponge/src/main/resources/luckperms.conf
@@ -69,6 +69,12 @@ use-server-uuids=true
 # in the LuckPerms cache.
 use-server-uuid-cache=false
 
+# If set to true, LuckPerms will allow usernames with non alphanumeric characters.
+#
+# Note that due to the design of the storage implementation, usernames must still be
+# 16 characters or less.
+allow-invalid-usernames=false
+
 # If LuckPerms should produce extra logging output when it handles logins.
 # Useful if you're having issues with UUID forwarding or data not being loaded.
 debug-logins=false