Leveraging historical behavioral data (e.g., sales volume and email communication) for future prediction is of fundamental importance for practical domains ranging from sales to temporal link prediction. Current forecasting approaches often use only a single time resolution (e.g., daily or weekly), which truncates the range of observable temporal patterns. However, real-world behavioral time series typically exhibit patterns across multi-dimensional temporal patterns, yielding dependencies at each level. To fully exploit these underlying dynamics, this paper studies the forecasting problem for behavioral time series data with the consideration of multiple time resolutions and proposes a multi-resolution time series forecasting framework, RESolution-aware Time series Forecasting (RESTFul). In particular, we first develop a recurrent framework to encode the temporal patterns at each resolution. In the fusion process, a convolutional fusion framework is proposed, which is capable of learning conclusive temporal patterns for modeling behavioral time series data to predict future time steps. Our extensive experiments demonstrate that the RESTFul model significantly outperforms the state-of-the-art time series prediction techniques on both numerical and categorical behavioral time series data.