Lim Cheng Kim was born the eldest daughter of a Hokkien Chinese family which owned tin mines in Selangor and had been established in Malaya for generations. Her mother, Soon Kui Sim, took over the management of her husband's tin mines in Rawang, when he was forced to retire due to illness. Being largely illiterate, she devised her own complex hieroglyphic bookkeeping system to manage the family's extensive finances. Loke's mother would even go to the mines personally and wake the labourers up to work by literally pulling them out of bed. Not having had the opportunity to be schooled, she was determined that her daughter would not be illiterate and sent the young girl to study at the Methodist Girls' School Kuala Lumpur by train – a journey of 50 miles each way.