Disclosed herein, among other things, are systems and methods for modular circuit component for a hearing assistance device flex antenna. One aspect of the present subject matter includes a universal apparatus for use with multiple hearing assistance devices. The apparatus includes a circuit module including an outer radial surface, the circuit module configured to provide electronics for a hearing assistance device. A flex circuit loop antenna is configured to be affixed to the outer radial surface, and the antenna is configured for wireless communication for the hearing assistance device. After the antenna is affixed to the outer radial surface, the circuit module is configured to be inserted into a plurality of different main hearing assistance device chassis. In various embodiments, the circuit module includes a retention feature and the antenna includes an opening configured to align with and receive the retention feature to affix the antenna to the circuit module.