Here is a list of opportunities for novel-/novella-in-flash manuscripts, including publishers of NIFs since the turn of the 21st century. In all cases, do check latest submission guidelines and be sure to confirm that the publisher is open to relevant submissions. If there is any uncertainty, sending them a polite query might be an option before sending a manuscript. Please note that some of these publishers will only accept submissions through agents. I hope to keep building this list. Several publishers have since closed or merged with other publishers and are therefore not listed here. If you are a publisher open to novellas-in-flash and would like to be listed, please let me know via this Contact form. [List updated 21st March 2023 – Paper Visual Art Books added. And 20th March – Cupboard Annual Pamphlet Contest added. 16th March 2023 – 2023 Moon City Short Fiction Award & Sundress Publications Annual E-chapbook Competition added. 28th February 2023 – Červená Barva Press added. 17th February 2023 – the Fugere Book Prize, Alien Buddha Press, And Other Stories, Broken Sleep Books, Fiction Attic, and the Watson, Little x Indie Novella Prize added. Selcouth Station removed.]

Small Press Publishers/Independent Publishers who have published more than one novella-in-flash/novel-in-flash in the last five years: 

Ad Hoc Fiction (NB Ad Hoc Fiction have mainly published novellas-in-flash arising from the B.F.F.A. Competition below, but occasionally publish additional novellas-in-flash outside of this.) 
Bamboo Dart Press
Ellipsis Zine
Fairlight Books 
Flash: the International Short-Short Story Press 
Reflex Press
Rose Metal Press
Truth Serum Press
V. Press

Competitions

Bath Flash Fiction Award Novella-in-Flash Competition – Annual competition since 2017, closing date late January – final year of competition 2023
Chestnut Review Prose Chapbook Contest – has been running annually since summer 2021. Although NIFs aren’t specified by name, guidelines encouragingly state: “We welcome all forms of prose manuscripts: fiction, CNF, or hybrid. Hit us with one powerful story or delight us with a series of flash. Blur genres or stay true to form. Surprise us. Challenge us. Manuscripts with more than one piece should feel cohesive and coherent.”
Ellipsis Zine – the magazine usually holds an annual flash fiction manuscript competition in the spring/summer (which is open to novellas-in-flash)
2023 Moon City Short Fiction Award – Although NIFs aren’t specified by name, guidelines encouragingly state: “for an original collection of short fiction…entries may include short shorts, short fiction, and/or up to one novella.” – Ends 1st May 2023
National Flash Fiction Day – Ran a N-I-F competition in 2021
Regal House Publishing – The 2023 Fugere Book Prize for Finely Crafted Novellas
Reflex Press Novella Award – For all kinds of novellas, but this competition has novellas-in-flash among its past winners. Closing date usually in January.
Retreat West Novelette-in-Flash Prize – Ran their competition in 2020 and 2021. 
Sandy Run Novella Award | Hidden River Arts– for all kinds of novellas, but open to novellas-in-flash
Sundress Publications Annual E-chapbook Competition – Although NIFs aren’t specified by name, guidelines encouragingly state: “poetry, fiction, nonfiction, and hybrid work are welcome” – deadline 31st May 2023
The Cupboard Annual Pamphlet Contest – prose manuscripts between 5,000 and 10,000 words. “We make no demands on content or genre, with the exception of verse poetry, which we don’t publish.” 
The Watson, Little x Indie Novella Prize – for novel-length manuscripts, style unspecified (three strands: characters & community, climate, crime fiction)

Independent Publishers who have recently published at least one book/pamphlet that could be described as a novella-in-flash/novel-in-flash (example listed): 

above/ground press (e.g. Off the Resting Sea)
Alien Buddha Press (e.g. Kahi and Lua)
And Other Stories (e.g. Somebody Loves You)
Broken Sleep Books (e.g. Go On)
CB Editions (e.g. The Absent Therapist, Days and Nights in W12)
Červená Barva Press (e.g. Saying Goodbye)
Civil Coping Mechanisms (e.g. I’m Not Saying, I’m Just Saying)
Counterpoint Press (e.g. Why Did I Ever, One D.O.A., One on the Way)
Keyhole Press (e.g. How to Predict the Weather)
Liquorice Fish Books/Cinnamon Press (NB prose poetry sequences that read like novellas – e.g. Ed’s Wife and Other Creatures & The True Story of Cowboy Hat and the Ingenue)
Shanti Arts Publishing (e.g. Paperboy)
University of Pittsburgh Press (e.g. All the Day’s Sad Stories, as part of The Physics of Imaginary Objects)

Independent publishers who have recently published novellas, flash fiction collections and/or hybrid books and have said that they are (or who may be) open to novella-in-flash/novel-in-flash manuscripts

Arachne Press (only open to authors who’ve already been published in one of their anthologies).
Driftwood Press
Emerge Literary Journal
Fiction Attic (online opportunity for N-I-Fs through serial instalments on Substack)
Fish Gotta Swim Editions
Fly on the Wall Press (although the publisher notes that they have so far preferred traditional novellas)
Leamington Books
Little Thorn Books (publishing novellas in the following genres: Victoriana, gothic, steam punk, magic realism and supernatural)
Louise Walters Books 
Paper Visual Art Books – for “novellas, ideally 20,000-30,000 words.” Window closing 31st March 2023. 
Peninsula Press
Renard Press
Running Wild Press / RIZE Press
Split/Lip Press
Sundress Publications (“particularly interested in prose collections that value genre hybridization, the lyric, flash, strange or fractured narratives, new fiction, experimental work, or work with strong attention to lyricism and language. These collections may be short stories, novellas, essays, memoir, or a mixture thereof.”)
Vagabond Voices

Larger publishers who have recently published books that could be described as novellas-in-flash/novels-in-flash (example listed):

4th Estate (e.g. republishing Play It As It Lays & The Atrocity Exhibition)
Arcade Publishing (e.g. Haunted Traveller)
Bloomsbury (e.g. republishing The House on Mango Street, The Collected Works of Billy the Kid & Coming Through Slaughter)
Faber (e.g. Grief is the Thing with Feathers, The Coma)
Granta (e.g. Dept. of Speculation, We the Animals, Weather)
Hamish Hamilton – an imprint at Penguin (e.g. Assembly)
Harper Collins (through various smaller imprints such as Harper Perennial, Flamingo & The Friday Project they have published books such as 253, The Lover and With a Zero at its Heart)
Jonathan Cape – an imprint at Vintage/Penguin/Random House (e.g. Two Pints, Two More Pints)
New York Review Books (e.g. republishing Pitch Dark & Speedboat)
Penguin Books (e.g. republishing Mr. Bridge & Mrs. Bridge & The History of Love)
Picador (e.g. Last Orders, The End We Start From)
Viking Books – an imprint at Penguin (e.g. The History of Love, The Midnight Library)
Vintage – an imprint at Penguin/Random House (e.g. 334, The Complete Two Pints)

If you want some help with problem-solving/rekindling a novella-in-flash project, I offer specialist mentoring to novella-in-flash writers. You can read about my NIF experience here. Feel free to get in touch via the form below: