The incident happened at the junction of Strawberry Dale Avenue and Mayfield Grove in Harrogate at around 11.50pm on Sunday 30 June 2019.
Two men aged in their 20s were walking along Strawberry Dale Road when they were approached by a man with a knife who threatened them and told them to empty their pockets. They both sustained a cut to their leg during the incident.
They were taken to Leeds General Infirmary for treatment, however, their injuries are not believed to be life-threatening.
The 18-year-old man remains in police custody at this time.