People’s differences in cognitive functions are partly heritable and are associated with important life outcomes. Previous genome-wide association studies of cognitive functions have found evidence for polygenic effects yet, to date, there are few replicated genetic associations. Here we use data from the UK Biobank sample to investigate the genetic contributions to variation in tests of three cognitive functions and in educational attainment. Genome-wide association analyses were performed for Verbal-numerical Reasoning (N = 36 035), Memory (N = 112 067), Reaction Time (N = 111 483), and for the attainment of a college or university degree (N = 111 114). We report genome-wide significant SNP-based associations in 20 genomic regions, and significant gene-based findings in 46 regions. These include findings in the ATXN2, CYP2DG, APBA1, and CADM2 genes. We report replication of these hits in published GWA studies of cognitive function, educational attainment, and childhood intelligence. There is also replication, UK Biobank, of SNP hits reported previously in GWA studies of educational attainment and cognitive function. GCTAGREML analyses, using common SNPs (MAF>0.01), indicated significant SNP-based heritability of 31% (SE = 1.8%) for Verbal-numerical Reasoning, 5% (SE = 0.6%) for Memory, 11% (SE = 0.6%) for Reaction Time, and 21% (SE = 0.6%) for Educational Attainment. Polygenic score analyses indicate that up to 5% of the variance in cognitive test scores can be predicted in an independent cohort. The genomic regions identified include several novel loci, some of which have been associated with intracranial volume, neurodegeneration, Alzheimer’s disease, and schizophrenia. Keywords: genetics, GWAS, cognitive function, reaction time, memory, educational attainment, reasoning, UK Biobank