An adjustable coupler apparatus for a trailer hitch includes a drawbar assembly and a hitch head assembly. The drawbar assembly is interconnected to a tow vehicle and includes an elongate bar and a drawbar angle adjuster that is pivotally interconnected and angularly adjustable relative to the bar. The hitch head assembly includes a ball component and a channel that is pivotally interconnected to the ball component. A horn is slidably received by the channel. The horn and the drawbar angle adjuster are selectively coupled to interconnect the trailer to the tow vehicle.