The slaty monarch (Mayrornis lessoni) is a species of bird in the family Monarchidae endemic to Fiji. Its natural habitat is subtropical or tropical moist lowland forests.
The slaty monarch was originally described in the genus Rhipidura. Alternate names include cinereous flycatcher, Fiji flycatcher, Fiji slaty flycatcher, slaty flycatcher (an alternate name shared with the Vanikoro monarch) and white-tipped slaty flycatcher.
There are two subspecies recognized:[1]