Surgical tools that can be used in single port laparoscopic procedures can include a low-profile handle assembly to minimize tool interference adjacent the incision site. For example, a handle assembly for a surgical instrument can have a generally in-line configuration extending linearly along a central longitudinal axis of an elongate shaft of the instrument. A linkage mechanism including a trigger, an actuation link, and an actuation shaft can be positioned within the in-line handle. The linkage mechanism can be pivoted between an open position in which end effectors of the instrument are open and a toggle position in which the end effectors are locked closed. A locking mechanism such as a ratchet mechanism can also be used to lock the end effectors. A surgical dissector can include gripping jaws having a curved profile or an angled elongate shaft to minimize tool interference and maximize visibility within a procedure site.