An adjustable wrench includes two plates, a handle unit, a rotary unit and a control unit. Each plate has a first toothed portion. The handle unit is located between the two plates and includes a handle and a toothed ring. The handle has a second toothed portion. The toothed ring has multiple third teeth and multiple fourth teeth. The third teeth are engaged with the second teeth. The fourth teeth are located between the first toothed portions of the two plates. The rotary unit is located between the two plates and has a first jaw and a second jaw. The control unit includes having a controlling member and a resilient member. The controlling member is connected to the plate and has fifth teeth defined in one end thereof. The resilient member contacts the controlling member to engage the fifth teeth with the first and fourth teeth.