diff --git a/setup.sh b/setup.sh
index d090c4e..53376a2 100755
--- a/setup.sh
+++ b/setup.sh
@@ -47,6 +47,22 @@ check_debian() {
     fi
 }
 
+# Check for required commands
+check_commands() {
+    local required_commands="useradd passwd sudo"
+    
+    for cmd in $required_commands; do
+        if ! command -v "$cmd" >/dev/null 2>&1 && ! [ -x "/usr/sbin/$cmd" ]; then
+            error "Required command '$cmd' not found. Please install it first."
+        fi
+    done
+    
+    # Special check for usermod which we use later
+    if ! command -v usermod >/dev/null 2>&1 && ! [ -x /usr/sbin/usermod ]; then
+        warn "usermod command not found. Will attempt to use full path."
+    fi
+}
+
 # Ask user about creating an additional user
 ask_additional_user() {
     echo ""
@@ -174,7 +190,13 @@ create_sysadmin_user() {
     
     # Add sysadmin to sudo group
     log "Adding $SYSADMIN_USER to sudo group..."
-    usermod -aG sudo "$SYSADMIN_USER"
+    if command -v usermod >/dev/null 2>&1; then
+        usermod -aG sudo "$SYSADMIN_USER"
+    elif [ -x /usr/sbin/usermod ]; then
+        /usr/sbin/usermod -aG sudo "$SYSADMIN_USER"
+    else
+        error "usermod command not found. Please install the passwd package."
+    fi
 }
 
 create_additional_user() {
@@ -195,7 +217,13 @@ create_additional_user() {
         
         # Add additional user to sudo group
         log "Adding $ADDITIONAL_USER to sudo group..."
-        usermod -aG sudo "$ADDITIONAL_USER"
+        if command -v usermod >/dev/null 2>&1; then
+            usermod -aG sudo "$ADDITIONAL_USER"
+        elif [ -x /usr/sbin/usermod ]; then
+            /usr/sbin/usermod -aG sudo "$ADDITIONAL_USER"
+        else
+            error "usermod command not found. Please install the passwd package."
+        fi
     fi
 }
 
@@ -579,6 +607,7 @@ main() {
     # Check prerequisites
     check_root
     check_debian
+    check_commands
     
     echo -e "${BLUE}=== Debian 12 Initial Setup ===${NC}"
     echo "This script will:"