Systems for dynamically authenticating users are provided. A system may receive a request to access functionality. In response to the received request, an authentication grid may be dynamically generated. The authentication grid may include a plurality of fields, each identifiable by a field identifier, and including one or more characters that may be used to authenticate a user. The authentication grid may be transmitted to a computing device of a user. A character for authentication may be identified by the system. In some arrangements, the system may generate a request for user input including a character appearing in the authentication grid. The user may identify the field and input the character appearing in the field. The system may receive the requested character and may compare it to the identified character for authentication. If the received character and the identified character match, functionality may be enabled. If a match does not exist, functionality may be disabled.