diff --git a/src/common-utils/README.md b/src/common-utils/README.md
index 3d21e8b3f..e5218bdb4 100644
--- a/src/common-utils/README.md
+++ b/src/common-utils/README.md
@@ -19,6 +19,7 @@ Installs a set of common command line utilities, Oh My Zsh!, and sets up a non-r
 | configureZshAsDefaultShell | Change default shell to ZSH? | boolean | false |
 | installOhMyZsh | Install Oh My Zsh!? | boolean | true |
 | installOhMyZshConfig | Allow installing the default dev container .zshrc templates? | boolean | true |
+| ohMyZshTheme | Oh My Zsh theme to use (e.g., 'robbyrussell', 'agnoster', 'fino'). Default is 'devcontainers'. | string | devcontainers |
 | upgradePackages | Upgrade OS packages? | boolean | true |
 | username | Enter name of a non-root user to configure or none to skip | string | automatic |
 | userUid | Enter UID for non-root user | string | automatic |
diff --git a/src/common-utils/devcontainer-feature.json b/src/common-utils/devcontainer-feature.json
index 14056e3a9..790a6d4b4 100644
--- a/src/common-utils/devcontainer-feature.json
+++ b/src/common-utils/devcontainer-feature.json
@@ -25,6 +25,11 @@
             "default": true,
             "description": "Allow installing the default dev container .zshrc templates?"
         },
+        "ohMyZshTheme": {
+            "type": "string",
+            "default": "devcontainers",
+            "description": "Oh My Zsh theme to use (e.g., 'robbyrussell', 'agnoster', 'fino'). Default is 'devcontainers'."
+        },
         "upgradePackages": {
             "type": "boolean",
             "default": true,
diff --git a/src/common-utils/install.sh b/src/common-utils/install.sh
index 313271d0a..622d5ea72 100755
--- a/src/common-utils/install.sh
+++ b/src/common-utils/install.sh
@@ -13,6 +13,7 @@ INSTALL_ZSH="${INSTALLZSH:-"true"}"
 CONFIGURE_ZSH_AS_DEFAULT_SHELL="${CONFIGUREZSHASDEFAULTSHELL:-"false"}"
 INSTALL_OH_MY_ZSH="${INSTALLOHMYZSH:-"true"}"
 INSTALL_OH_MY_ZSH_CONFIG="${INSTALLOHMYZSHCONFIG:-"true"}"
+OH_MY_ZSH_THEME="${OHMYZSHTHEME:-"devcontainers"}"
 UPGRADE_PACKAGES="${UPGRADEPACKAGES:-"true"}"
 USERNAME="${USERNAME:-"automatic"}"
 USER_UID="${UID:-"automatic"}"
diff --git a/src/common-utils/main.sh b/src/common-utils/main.sh
index b0fd2f3b0..f41da3e59 100644
--- a/src/common-utils/main.sh
+++ b/src/common-utils/main.sh
@@ -13,6 +13,7 @@ INSTALL_ZSH="${INSTALLZSH:-"true"}"
 CONFIGURE_ZSH_AS_DEFAULT_SHELL="${CONFIGUREZSHASDEFAULTSHELL:-"false"}"
 INSTALL_OH_MY_ZSH="${INSTALLOHMYZSH:-"true"}"
 INSTALL_OH_MY_ZSH_CONFIG="${INSTALLOHMYZSHCONFIG:-"true"}"
+OH_MY_ZSH_THEME="${OHMYZSHTHEME:-"devcontainers"}"
 UPGRADE_PACKAGES="${UPGRADEPACKAGES:-"true"}"
 USERNAME="${USERNAME:-"automatic"}"
 USER_UID="${USERUID:-"automatic"}"
@@ -570,7 +571,13 @@ if [ "${INSTALL_ZSH}" = "true" ]; then
             if ! [ -f "${template_path}" ] || ! grep -qF "$(head -n 1 "${template_path}")" "${user_rc_file}"; then
                 echo -e "$(cat "${template_path}")\nzstyle ':omz:update' mode disabled" > ${user_rc_file}
             fi
-            sed -i -e 's/ZSH_THEME=.*/ZSH_THEME="devcontainers"/g' ${user_rc_file}
+            # Validate theme name to prevent injection (allow alphanumeric, hyphens, underscores, and dots)
+            if echo "${OH_MY_ZSH_THEME}" | grep -qE '^[a-zA-Z0-9_.-]+$'; then
+                sed -i -e "s/ZSH_THEME=.*/ZSH_THEME=\"${OH_MY_ZSH_THEME}\"/g" ${user_rc_file}
+            else
+                echo "Warning: Invalid theme name '${OH_MY_ZSH_THEME}'. Using default 'devcontainers' theme."
+                sed -i -e 's/ZSH_THEME=.*/ZSH_THEME="devcontainers"/g' ${user_rc_file}
+            fi
         fi
 
         # Copy to non-root user if one is specified
diff --git a/test/common-utils/custom-zsh-theme.sh b/test/common-utils/custom-zsh-theme.sh
new file mode 100755
index 000000000..6d8dd90da
--- /dev/null
+++ b/test/common-utils/custom-zsh-theme.sh
@@ -0,0 +1,15 @@
+#!/bin/bash
+
+set -e
+
+# Optional: Import test library
+source dev-container-features-test-lib
+
+# Definition specific tests
+check "zsh" zsh --version
+check "oh-my-zsh installed" test -d $HOME/.oh-my-zsh
+check "zsh theme is fino" grep 'ZSH_THEME="fino"' ~/.zshrc
+check "default shell is zsh" bash -c "getent passwd $(whoami) | awk -F: '{ print \$7 }' | grep '/bin/zsh'"
+
+# Report result
+reportResults
diff --git a/test/common-utils/scenarios.json b/test/common-utils/scenarios.json
index ee138ca22..9c5137c20 100644
--- a/test/common-utils/scenarios.json
+++ b/test/common-utils/scenarios.json
@@ -284,5 +284,17 @@
         "features": {
             "common-utils": {}
         }
+    },
+    "custom-zsh-theme": {
+        "image": "ubuntu:jammy",
+        "remoteUser": "devcontainer",
+        "features": {
+            "common-utils": {
+                "installZsh": true,
+                "installOhMyZsh": true,
+                "ohMyZshTheme": "fino",
+                "configureZshAsDefaultShell": true
+            }
+        }
     }
 }
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