The aim of this project is to integrate structural and stratigraphic data from syn-tectonic strata of the Oliana anticline, Spanish Pyrenees with numerical models of fault-related folding, syn-tectonic sedimentation and drainage network evolution, to investigate the tlu'ee-dimensional expression of fault-related folds. The focus of this work has been on three-dimensional fold morphology, associated syn-tectonic strata, and the controls exerted on the spatial and temporal development of drainage networks around active folds. Analysis of map-view syn-tectonic stratal geometries on the forelimb of the Oliana anticline suggest a complex relationship between fold growth, syn-tectonic sedimentation and erosional processes. A large erosive unconformity was created during the initial stages of fold development, which was later infilled by further syn-tectonic sediments. Key, traceable sedimentary packages on the forelimb define a tight, laterally twisted fold structure, with marked overturning of the lower sequence of syn-tectonic strata. Fold uplift and movement on a hitherto unrecognised back-thrust led to the deformation of the syn-tectonic strata, without deformation of the underlying pre-tectonic marls. Interpretation of the structural data stresses the complex stratal relationships that can arise within syn-tectonic strata in three-dimensions. Numerical modelling of trishear fault-propagation folding and syn-tectonic sedimentation in three-dimensions allows existing fault and fold growth models to be tested, and critically compared with natural examples of both fault and fold morphology and syn-tectonic stratal geometries. Numerical models of three-dimensional trishear fault-propagation folding developed here include syn-tectonic sedimentation both as background sedimentation and diffusional hillslope processes. Simple models of fault growth have been tested and reveal that (i) linear-taper fault displacement profiles do not produce realistic fault or fold morphologies, regardless of lateral fault propagation rates; (ii) block-taper fault displacement distributions combined with slow lateral propagation produce linear lateral fold profiles and lead to the development of along-strike growth triangles when sedimentation rates are high, whereas when sedimentation rates are low, offlap geometries result; (iii) If the lateral propagation rate is rapid (or geologically instantaneous), strike-parallel rotation of the syn-tectonic strata near the fault tips is observed; high sedimentation rates relative to rates of uplift result in along-strike thinning over the structural high, while low sedimentation rates result in pinchout against it; (iv) the most rapid lateral propagation rates produce the most realistic geometries. Numerical models of three-dimensional fault-propagation fold growth and consequent bedrock drainage evolution confirm that linear-taper displacement distributions do not produce realistic fold morphologies. Drainage networks developed on folds developed by rapid along-strike propagation and more block-like lateral displacement distributions are more comparable to natural examples of consequent drainage patterns above active fault-related folds, and stress the intimate relationship between fold morphology and drainage patterns. Consequent drainage models developed for two coeval fault-related folds highlight the along-strike changes in drainage densities and surface dissection, and suggest that drainage patterns may record fold segment linkage. Numerical models of three-dimensional fault-propagation folding and regional drainage highlight the importance of the rate of lateral fold propagation and sediment flux among the controls of regional drainage defeat and diversion. The model replicates stream capture by headward erosion, and the defeat and diversion of regional drainage as a consequence of fold uplift. The range of modelling parameters used here did not reproduce the conditions for antecedent drainage evolution, suggesting this phenomenon may be the exception rather than the rule.