In today’s telecom sector business environment, consumers are constantly demanding for higher quality delivery of services and products. Although service quality in mobile sector is improving, evidence suggests that there are numerous quality service gaps existing in the mobile telecom sector in Zambia. At the same time, complaints from dissatisfied customers regarding poor service quality delivery have escalated lately. This study was conducted to measure the level of Quality of Service (QoS) being experienced by the end user of various services offered by service providers as compared to quality of service parameters set by the National Regulatory Authority (ZICTA). The study focused on Call Setup Time (CST), Call Drop Rate (CDR), Call Setup Success Rate (CSSR), Mean Opinion Score (MOS)/Audio Voice Quality, Successful SMS Rate (SSR) and SMS Delivery Time. The study has revealed that all the service providers operating in the Zambian mobile telecom sector have either failed to meet the minimum target as set in the quality of service guidelines or they are not consistent in the provision of their services.