Botaka, 22, had his medical at Thorp Arch and the paperwork to make him Leeds' eighth summer signing should be completed today.
The DR Congo winger has been offered a two-year deal at Elland Road with the option of a third.
Botaka claims he is excited about coming to Leeds, but sad that he is leaving his friends in Holland.
"I'm very happy, but at the same time I regret that I won't see my buddies, brothers and colleagues," he said. "But I know that we will always stay in touch. This is a new adventure for me."