Country Grammer is the fifth foal of Arabian Song (Forestry), herself a winner. She is also the dam of the graded stakes-placed Joyful Cadence (Runhappy), third in the Grade 3 Miss Preakness S., and of the 2019 filly Gharz, twice placed from four starts in Saudi Arabia. Arabian Song is a half-sister to Bodes Galaxy (Marju), placed in the Gr.2 Richmond Stakes and the Gr.2 Gimcrack Stakes.

Second dam Prima Centauri (Distant View) bred four winners, among them Arabian Song and Bodes Galaxy.

Third dam Willstar (Nureyev), a winner, heads a branch that includes the top-level winner Etoile Montante (Miswaki), who took the Gr.1 Prix de la Forêt, her multiple graded winner daughter Starformer (Dynaformer), the Grade 3 Hurricane Bertie S. winner Obligatory (Curlin) and the multiple graded winner Bonny South (Munnings). Etoile Montante is also the grandam of Flavius, a triple Listed winner placed at Group 2 level. Obligatory, who also won the Grade 2 Eight Belles Stakes, is out of Willstar's Listed-winning daughter Uno Duo (Macho Uno), and Bonny South, winner of the Grade 2 Fair Grounds Oaks and placed in several Grade 1 races, is out of Touch The Star (Tapit).

Willstar's other daughters include Starfan (Lear Fan), placed in the Sceptre Stakes, then a Listed race, and dam of Glaswegian, winner of the Gr.3 Prix de Fontainebleau, and Jolie Etoile (Diesis), dam of Preferential, winner of the Listed Prix des Tourelles, and grandam of King Carney, winner of the Listed Silver Tankard Stakes. The fourth dam Nijinsky Star (Nijinsky) is the ancestress of the Group 1 winners Sightseek (Distant View), Kings Will Dream (Casamento), Tates Creek (Rahy) and Special Duty (Hennessy) and of the sire Expert Eye (Acclamation).