Mars in 12th House Synastry, Explained By an Astrologer

If there’s one thing you should know about Mars in 12th house synastry, it’s this; it’s serious, intense, and puts both parties in an extremely vulnerable position.

When fiery, straight-shooting Mars touches the elusive and uber secretive 12th house, all of their subconscious secrets, fantasies, dreams, visions, and even traumatic experiences are brought to life.

There’s huge potential for both unwavering support and complete manipulation in this dynamic.

a photo showing either soulmates and a couple in therapy
The potential for either a deeply supportive or deeply troubled relationship

How it plays out fully depends on how extreme the energy of both the house and planet person is. That’s why I call it the placement of both soulmates and enemies – it can go in two completely opposite directions.


Having Mars overlay in the 12th house doesn’t mean your relationship is completely doomed!

Whilst Mars is known for its aggressive, fiery, and ill-tempered nature, it actually energizes the 12th house, activating all of its components, traits, and energy.

If Mars is healed, this can be a fantastic, almost soul-mate connection. The kind where you low-key feel as though a part of you is missing without the other person being there.

The Mars native and house person can actually form a beautiful healing alliance, bringing all of their subconscious fears and worries to light. They can unearth their deepest trauma, grief, and sorrow and work to heal it together.

This relationship strips back everything that was previously learned in all the eleven houses and either boosts it or challenges it.

The downside? There’s a tendency for this kind of connection to fizzle out though; at first, it might seem magical, and then as it progresses it morphs into a strange connection with a lack of passion and understanding.

Based on my own experience, I would say the house person feels the effect of this connection much more than Mars native. 


a couple hugging each other under a sunset in the field


The Mars person provides intense catalytic energy to help the house person unearth qualities they never even knew existed.

They’ll push the house person outside of their comfort zone in all areas of life (and that can be a good or bad thing, I guess). Mars will bring out the side of them they’ve been too scared to face for years.

The only caveat? There’s absolutely no hiding from it. House person can’t retreat from it because Mars carries the most forceful energy of all the planets.

Mars can unintentionally dig deeper and ask lots of intrusive questions without realizing it, causing the house person to open up when they might not really want to.

Radical change, growth, and deep internal transformation is on the horizon, whether they like it or not.


Mars represents action, progression, and forward movement. The forcefulness and determination of the Mars native encourages the 12th house person to bring their dreams and visions to life.

Whatever dreams the house person has sacrificed or buried over the years, they’ll have a chance to review and revive them if they so wish.

Likewise, the 12th house person will activate the Mars native’s intuition; it will encourage them to tap into the unknown and hone in on their instinct when navigating their next steps in life. Something which will feel very alien to the Mars person.


Remember how I said this placement can be extremely vulnerable? This is it. The Mars person will want to know everything about the house person; what makes them tick, how they think, what their deepest and darkest psychological fears are.

If Mars person is capable of handling such a responsibility, they practically become the house person’s therapist, nudging them to see just what’s beyond their grasp.

That said, Mars needs to be patient and understanding here. They need to exhibit the absolute best of their planet’s qualities to make this work, otherwise, it will stray into the realms of manipulation.


At its absolute best, this connection has the potential to be very spiritual by nature too, where both partners come to realize that everything in the Universe is interconnected, including themselves.

This lends to a better understanding of one another’s feelings, emotions, and desires.

Other gifts:

  • A sacred relationship
  • Love at first sight sort of connection
  • Intuitively knows each other’s desires, wants, and needs
  • Brilliant partners to confide in
  • Intense physical chemistry and love life, especially in the beginning


a troubled coupled holding hands


There’s no doubt about it, past traumas will be reactivated and this is the trickiest part of the relationship to navigate.

The Mars person encourages (sometimes forces) the house person to dig deep into their shadow traits, bringing difficult topics up that the house person would rather leave buried.

If the house person feels triggered, there’s potential for them to retreat, feel creeped out, go into full emotional meltdown or embody the Martian energy and retaliate.

Remember, the 12th house is all about the unknown (uncharacteristic behaviour is likely here).

Likewise, if the Mars native feels they have to hide their direct nature, they’ll either explode, taking out their anger on innocent bystanders or implode, leading to self-sabotage and self-hate. 


Mars will have deep insights into the 12th house native’s subconscious, their deepest fears and worries, and vice versa. There’s a massive potential for manipulation, using your most vulnerable parts against you.

I will say if you notice this playing out, this connection isn’t likely to get better, only worse with time. 


Whilst both parties might be able to keep the relationship going for years, if the disconnection is too strong, they’ll seek what they’ve repressed with one another with other people instead.

There might be a deep want to repair the relationship from both sides, but neither will know exactly how to do it. 

Other challenges:

  • Unrealistic relationship held together by fantasy and hope
  • Difficult marriage and long-term relationship, lots of ups and downs
  • Possibility for a situationship, not really knowing where you stand
  • Mars person might feel unappreciated in their efforts
  • Hidden hostility between both partners, though you might not be able to put a finger on what it is
  • Possible unrequited love after just weeks or months of knowing each other
  • In an extremely negative relationship where both people show the worst of each planet and house, the 12th house person thinks Mars is rude and obtrusive, Mars person thinks 12th house person is weak and indecisive


If both of you have got Mars in each other’s 12th house, this is a very secretive relationship, not necessarily in a good way.

This is where that secret enemy label comes into play. Backstabbing, lying, and cheating is heightened with this placement. They might be loving and smiling to your face, but behind your back, another story is being told.

Lots of things going on behind your behind. You might also feel a need to keep your cards close to your chest in fear of your weaknesses being used against you. Overall, not a great placement.

Of course, astrology isn’t black and white, so please consult other surrounding placements to determine true compatibility. 



  • A relative who loves and accepts you for who you are
  • Physically supports you when you’re emotionally weak


  • Flighty parents or family members who you can’t rely upon
  • The family member who sabotages your success and keeps aiding you in bad habits
  • Their own fears playing out which keep you believing you’re doomed to follow a similar path
  • The relative who makes you feel uneasy during conversations

Continue Your Journey of Discovery

a picture of charlotte, the founder of Typically Topical, smiling


Charlotte Kirsten

Charlotte is a renowned Trauma Psychotherapist, Astrologer, and Founder of Typically Topical. With a background in psychology, astrology, and esoteric practice, her soulful guides are read by over 300,000 people every month.

For her work, she's been named UK Womenspire Woman of the Year, awarded the title of Yale Young Global Scholar, and featured as an expert across major networks such as, Best Life, Oprah Winfrey Network, BBC, Soul & Spirit, Psychology Today, Pop Sugar, Well & Good and Cosmopolitan. You can find her on Twitter.

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