cond decade of the twentieth century there was a noticeable differ- ence in the QoS regulation approaches between countries with developed (i.e. mature) telecom markets and those with developing (i.e. less mature) telecom/ICT markets. In competitive and developed telecom/ICT markets, QoS enforcement is targeted mainly at notices and publication of QoS measurements by using a given set of KPIs appro- priate for targeted services, with the aim of informing customers (i.e. end-users for the given services) SO they have enough necessary information when selecting or switch- ing telecom operator. However, some customers with low WTP may choose lower QoS, and vice versa. Therefore, for critical services, which are important to society and to the public (not only to the operators and customers), the NRA may enforce measures to improve QoS if the QoS is essential for the service functioning, for public safety (e.g. intelligent transportation systems), or for the society as a whole (e.g. development of the digital society by moving public functions into the digital world, such as their pro- visioning over the public Internet). Also, emerging technologies such as SDN and NFV 9 QoS Regulatory Framework together with cloud computing (which is used for most of the data-based services) lead to network slicing and then different KPIs are required for different network slices that will be used for different types of services (e.g. massive machine type communication, ultra-reliable low-latency communication, ultra-broadband) [13]. In less mature telecom/ICT markets, the NRAs may and should consider applying financial penalties as a possible tool for QoS, after all previous options for improving the QoS of the given telecom operator have been implemented and are not showing results (e.g. notices sent to telecom operators to improve QoS in a given time period). However, one should note that there are no global rules for applying penalties for the purposes of QoS enforcement, SO that should be done by considering all relevant factor