The frontal eye field (FEF) plays a well-established role in the control of visual attention. The strength of an FEF neuron's response to a visual stimulus presented in its receptive field is enhanced if the stimulus captures spatial attention by virtue of its salience. A stimulus can be rendered salient by cognitive factors as well as by physical attributes. These include surprise. The aim of the present experiment was to determine whether surprise-induced salience would result in enhanced visual response strength in the FEF. Toward this end, we monitored neuronal activity in two male monkeys while presenting first a visual cue predicting with high probability that the reward delivered at the end of the trial would be good or bad (large or small) and then a visual cue announcing the size of the impending reward with certainty. The second cue usually confirmed but occasionally violated the expectation set up by the first cue. Neurons responded more strongly to the second cue when it violated than when it confirmed expectation. The increase in firing rate was accompanied by a decrease in spike-count correlation as expected from capture of attention. Although both good surprise and bad surprise induced enhanced firing, the effects appeared to arise from distinct mechanisms as indicated by the fact that the bad-surprise signal appeared at a longer latency than the good-surprise signal, and by the fact that the strength of the two signals varied independently across neurons.Significance Statement Neurons in the macaque frontal eye field (FEF) respond strongly to cues predicting rewards. Their firing might be related to the representation of value or to the capture of attention. We set out to resolve this issue by monitoring neuronal responses to cues conveying surprising information about upcoming rewards. We find that surprising cues elicit enhanced responses regardless of whether the surprise is good (more reward than expected) or bad (less reward than expected). These findings, which constitute the first evidence for surprise-driven activity in the FEF, are most harmonious with an interpretation based on capture of attention.