Oscillations have been observed in numerous areas of science and engineering. Some typical oscillations relate to pendulums, business cycles, and neural dynamics. Nonlinearities lead to complex behaviours of oscillations, especially chaos, which has received significant attention since 1963 when Lorenz observed experimental chaos in a nonlinear weather model. Chaotic oscillators exhibit rich dynamics and have been used in numerous engineering applications ranging from cryptography, encryption, secure communications, random signal generators, through-wall radar, to robotics.

Various chaotic oscillators have been reported in the literature in the last three decades. Still, there are many topics of interest in the chaos literature, such as discovering new chaotic oscillators with special features (like multistability or megastability), and/or with novel phenomena (like hidden attractors or extremely large events). Experimental studies of oscillatory systems via simulations and circuits support us in understanding the modelling phenomena and also developing practical applications. Advanced techniques in different areas such as memristors, memristive devices, field programmable gate arrays‎ (FPGA), field-programmable analogue arrays (FPAA), neural networks, and machine learning provide effective tools to study and implement chaotic oscillations, which have attracted great progress in recent years. Moreover, there are still various challenging problems in theory, experiments, and control, as well as fractional-order chaotic models, which should be investigated.

The aim of this Special Issue is to present advanced contributions in chaotic oscillators with modelling, bifurcation analysis, circuit design, or control applications. We encourage authors to submit original articles related to all Special Issue’s aspects. Review articles introducing the current state of the art are also especially welcome.

Potential topics include but are not limited to the following:

• Bifurcation analysis and qualitative study of chaotic systems
• Chaotic oscillators and secure communications
• Chaotic oscillations in fractional-order differential equations
• Circuit design of chaotic oscillators
• Control and synchronisation of chaotic oscillations
• Emerging technologies for implementing oscillators
• Experimental chaotic oscillations in practical systems
• Fractional order chaotic oscillators and applications
• Hyperchaotic oscillators and applications
• Modelling, analysis and computational methods of chaotic oscillations
• Practical applications of chaotic oscillations
• Self-excited and hidden attractors in chaotic oscillators