She was the eldest daughter of Charles I, Duke of Brunswick-Wolfenbüttel, and his wife, Philippine Charlotte of Prussia, sister of Frederick the Great.

[1][2] This was an attempt to improve relations with Prussia, as Sophie Caroline was a niece of Frederick II of Prussia and George II needed Prussian troops to help offset the alliance between France and Austria that had occurred as a result of the Diplomatic Revolution.

The prince's mother Augusta, Dowager Princess of Wales, thwarted George II's plans, however, which increased tensions within the British royal family.

George and his mother's refusal also reflected another changing reality in British foreign policy: the relationship with the Electorate of Hanover.

[3] The Prince of Wales and his mother however did not possess the same attachment to Hanover, thus influencing their decision to reject a match with Sophie Caroline.