Word Grammar (WG), a dependency grammar, has historically permitted mutual dependency, a structure where two words depend on each other. This paper re-evaluates mutual dependency within WG, focusing on contradictions arising when dependency relations are inherently tied to word-order via WG’s ‘landmark’ relation. It is argued that mutual dependency which involves conflicting landmark relations is untenable. I examine earlier WG analyses of English dependent interrogatives and free relatives, which were the principal motivators for mutual dependency analyses. It is proposed that dependent interrogatives do not require mutual dependency and are better analysed with the verb as the head, with selection being semantic. Free relatives, however, with their matching effects where the wh-word is head, necessitate a form of mutual constraint. A solution is offered by refining WG’s theory of word-order and its relationship to extraction, by distinguishing between the general relationship of word-order, ‘landmark’ and a distinct relation of word-order that is part of the extraction start-rule. This approach allows for mutually constraining relations in free relatives without contradictory landmark assignments, thereby preserving a coherent theory of word-order while accommodating mutual dependency.