It can depend on whether or not your area is subject to extreme heat or cold conditions but the usually recommended oil is SAE 10W-30.
The 2005 Toyota Highlander has double overhead cam (DOHC).
Toyota ATF Type IV is the only recommended fluid.
The 2008 Toyota Highlander has double overhead cam (DOHC).
The 2010 Toyota Highlander has double overhead cam (DOHC).
The 2006 Toyota Highlander has double overhead cam (DOHC).
The 2004 Toyota Highlander has double overhead cam (DOHC).
The 2003 Toyota Highlander has double overhead cam (DOHC).
The 2001 Toyota Highlander has double overhead cam (DOHC).
The 2009 Toyota Highlander has double overhead cam (DOHC).
The 2013 Toyota Highlander has double overhead cam (DOHC).
The 2002 Toyota Highlander has double overhead cam (DOHC).
The 2007 Toyota Highlander has double overhead cam (DOHC).