The Avro 504C was the most important single-seat fighter variant of the basic Avro 504 and was employed in some numbers by the RNAS.

The Avro 504C was the most important single-seat fighter variant of the basic Avro 504 and was employed in some numbers by the RNAS.

The Avis I was intended for service with the clandestine Hungarian air arm.

The Avis II embodied some aerodynamic refinement.

The Avis III was a more powerful derivative of the Avis I with a revised structure.

The Avro 521 two-seater was intended for the long-range and escort fighter tasks.

The Avro 527 was the final fighter derivative of the basic Avro 504.

The Avro 530 was intended to compete with the Bristol F.2A but suffered protracted gestation.

The Avro 531 Spider was an exceptionally maneuvrable private-venture design by Roy Chadwick.

Of extremely clean design by contemporary standards, the Avro 566 Avenger was eventually modified for racing as the Avro 567 Avenger II.