The Overlooked Role of Mercury in Relationships

Natal Mercury is often glossed over in the astrology of love and relating. The planet of communication and information gets bypassed in the rush to focus on juicier planets, like Venus or Mars. Mercury may not be sexy, but it has a lot to say about how you approach partnerships. If natal Mercury rules/sits in one of your relationship houses (5th or 7th) or conjuncts Venus or Mars, its influence on your love life will be obvious. I’m not going to address those scenarios here, but I am going to look at examples where natal Mercury is not obviously connected to a relationship planet or house.

When Mercury Dominates

Your Mercury is not only responsible for communication with partners (and potential partners) — it dictates how you view love, sex and relating. It can provide the key to relationship behaviors that don’t seem to fit with the profile of your Sun, Moon, Venus or Mars. When natal Mercury forms a hard aspect to one of the slower moving natal planets (Jupiter, Saturn, Uranus, Neptune, Pluto) your mental processes and style of communication may dominate your approach to romance (especially if the characteristics of that planet are amplified by Mercury’s sign and/or house position).

For example, your Sun (ego) and Moon (needs) are in light and flirty Libra. Your Venus (how you relate) and Mars (sexual energy and how you take action) are in adventurous Sagittarius. Conventional astrological wisdom suggests that you should have a light touch in relationships; you’re happy to float on the surface. And while it’s true that you like to keep things moving, you fixate on the people you’re attracted to. This isn’t the usual infatuation that most experience. You become obsessed, spending weeks scouring the internet for information on your latest crush, and getting background checks performed on them (all before your first date). Once you’re in a relationship, you develop suspicions that your partner may be cheating. You ask them odd questions that are designed to trip them up, so they admit the “truth” about what they’ve really been doing. If we look at your Mercury, we see it’s in Scorpio, conjunct Pluto (ruler of Scorpio). Your thinking is locked into a pattern of suspicion and survival, driven by Pluto’s compulsive need for control. Everything that happens is put through the mental, Scorpio filter of psychological probing.

Or, maybe most of your planets are in the rational, grounded Earth signs. And yet, you consistently run into scenarios where you want one thing from your partners, but end up getting another. Secrets and deception color all your relationships. Your Mercury is in your hidden 12th House, opposite natal Neptune. Mercury in the 12th can make it difficult to get your point across, because it is in your blind spot; your ideas are unclear to everyone, including yourself. You may end up holding back information from partners, not because you are being consciously deceptive, but because you’re not clear on what you want to say. The opposition to Neptune adds another layer of difficulty, as your statements shift like smoke, so you can avoid being pinned down in an argument. And, you don’t want to hurt anyone’s feelings. You do this without being fully conscious of it.

The above examples are just that … examples. The great thing about any challenging Mercury issue is that you can think your way through it. Mercury responds to focused awareness and conscious efforts to bring out an influencing planet or sign’s higher energy. Pluto/Scorpio Mercury can turn that penetrating analysis on itself, while giving a partner the gift of profound conversation and focused (but healthy) attention. 12th House Mercury/Neptune can work on clarifying ideas and communication, while the partner benefits from its sensitivity and gentle, forgiving approach.

Conflicting or Harmonious Styles of Communication

In synastry, Mercury is usually the last thing someone wants to look at during the initial rush of love (or lust). But difficult aspects can add significant challenges, and harmonious aspects can add effortless glide to a relationship. Hard aspects from partner A’s Saturn to partner B’s Mercury will give the Mercury person the impression that they aren’t free to express themselves. Saturn may be dismissive of Mercury’s contributions. If these issues aren’t addressed, they can become corrosive. One person’s Mercury conjunct the other’s Moon gives Mercury an uncanny ability to “just know” what the Moon is feeling (like a window into their heart). Meanwhile, Moon will instinctively know how to respond to Mercury. These two barely have to speak to each other; there’s an almost psychic link.

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If Mr. Aries has natal Mercury conjunct Mars (action) and Uranus (sudden change) in Aries (ruled by Mars) his thinking/speaking is going to be impulsive and blunt. Each time he opens his mouth, he lowers the hammer without thinking about who’s being crushed. The synastry with his partner (Ms. Libra) is firing on all cylinders: harmonious aspects between their Sun and Moon, Mars conjunct Venus, some nice Saturn contacts (for stability). But Ms. Libra has a natal square between her Mercury (in Libra) and Saturn (in Cancer). Mercury in Libra is polite, and Saturn’s limits clamp down, resulting in a communication style and thought processes that are achingly correct and careful. Even if Aries and Libra’s Mercurys don’t aspect each other, communication will still be an issue. Over time, Aries may become impatient with Libra’s hesitancy to speak her mind. Libra will find Aries’ sudden outbursts to be rude and embarrassing. How big an issue this becomes depends on how important communication and intellectual rapport is for each of them.

It’s true that you cannot look at one planet in a chart and draw conclusions about someone’s approach to relationships. That’s not what this article is attempting to do. Rather, it’s illustrating how a planet that’s not usually associated with sex or romance can play just as significant a role as Venus or Mars. When it comes to love, what goes on in your head is as important as what unfolds in your heart.

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About Nadia Gilchrist

Nadia Gilchrist offers over 19 years of experience in astrology. Her writings and personal consultations focus on applying practical astrological analysis to the real world. Nadia blogs regularly at Ruby Slipper Astrology.


  1. I am your Ms. Libra here.

    Libra Mercury and Cancer Saturn in a 4 degree square. But the twist is that Uranus is conjunct my Mercury, though out of orb to be squaring Saturn.

    Yes, the painfully correct way of speech (with a touch of authority) does fit me most of the times. But i also tend to speak suddenly/out of turn (Uranus) and come up with radical stuff that sometimes make people spill their wine at parties…..:( Over the years i have learnt to hold my tongue though.
    I was smiling when i recently read one of your older posts where you mentioned someone tweeting about her miscarriage during a board meeting. I too am a person prone to saying such stuff and regretting later.

    Just curious, what would be the case if natal Uranus was square Mercury instead? Basically what is the difference between a square and a conjunction to mercury by an outer planet in a natal chart?

  2. And I am your Ms Scorpio 🙂

    Scorpio mercury 21 deg 2H. Moon, venus and mars in Sag, sun in scorpio too. I usually sense all I need to know long before I start looking things up. It was about a year before I started looking at synastry with my friend, and that was to confirm I wasn’t imagining things and it was more than just a crush.

    My mercury falls between my friend’s natal uranus 20 scorpio 12H, and his AC 22 scorpio. So I’m in his blind spot. It’s true he is useless at keeping secrets from me, and it’s true about the psychic connection. I noticed it works both ways and we don’t have to be physically present either, seems to be across the ether. His natal moon is opposite my mercury at 19 Taurus. It’s a bit freaky to feel so exposed sometimes, although it’s really nice not to have to explain things to the nth degree. It’s also a window into each other’s denial. Sometimes, we’re not aware of the lies we tell ourselves and it’s unsettling when someone comes along and sees past them.

    His mercury is 28 Sag 2H and falls in my 3H. I can’t see any hard aspects in our charts. Mine is sextile my uranus and pluto. We both have natal trine to chiron in our charts. When times are hard, we both know the right thing to say and when, and it also means we’re gentle with each other’s secrets. We let each other have them and wait till we say, and try not to say we already knew. So, for example, I know how things have progressed with who he’s with right now, and I know (feel) it’s a bad decision. Feels like it needs to happen, you have to trust the process, so I’m not punishing him. In the fullness of time, I’ll find out if I’m right. Thanks, Nadia 🙂

  3. So true. Ive got a 11th house Virgo Sun and a 11 house Leo Mercury, born on a day when it stationed direct, accurately squaring 2nd house Scorpio Neptune and ruler of my 12th house. Clarity in communication is absolutely not my strength, but I tell stories, remember things Ive never been told and I connect totally to my friends. Don’t ask me to tell the truth, ask me to tell a fairy tale and I’m yours..

  4. I have really tight mercury aspects with my boss (someone I communicate intensely with every day).
    Her 10th house moon conjuncts my 9th house mercury to the degree (19 pisces).
    My 10th house venus/mars conjunction 19 aries opposes her 4th house mercury/pluto conjunction 20 libra. I’ve noticed we both have alot of planets at these degrees in other signs so alot of planets are activated. We communicate very well at times, and not so well other times. I find her harsh, she finds me confusing at the worst of times. All in all, it’s a work relationship that challenges me to grow in the best possible ways.

    So yes Nadia, you’re right, mercury is not to be underestimated and it definitely depends on where mercury rules and is located. Mine is in my 9th house very near the MC, and I work in a job where communication is absolutely crucial!

  5. @marion
    The square is discordant, the conjunction unifies. Mercury conjunct Uranus blends the mental processes with Uranus’ innovation (although thinking/talking can still be scattered) while the square increases scattered thinking and adds extreme impatience (and sometimes rudeness) to Mercury. There’s still innovation with the square, but it’s expressed in a jarring way.

  6. @Kisses
    Mercury in Scorpio can certainly be patient.

  7. @Mads Elung-Jensen
    The 11th House Leo energy would emphasize the public performance aspect as well (with Neptune for creativity and sensitivity).

  8. @Ellie
    That harshness would be her Mercury/Pluto. Even though it’s in Libra, Mercury/Pluto has a tendency to strip away the facade.

  9. “For example, your Sun (ego) and Moon (needs) are in detached Aquarius….If we look at your Mercury, we see it’s in Scorpio, conjunct Pluto (ruler of Scorpio).”

    If Mercury and Sun are never more than 28 degrees apart form each other, then how can anyone ever have natal Sun in Aquarius and natal Mercury in Scorpio? Even if the Mercury is at the end of Scorpio and Sun is at the beginning of Aquarius, that still leaves all of Sagittarius and Capricorn (sixty degrees) in between them. Granted the example you have used is meant only to illustrated the point you’re trying to make (that mercury matters in relationships) but even then was is it really that hard to come up with an example that actually can happen in real life?

  10. Tell me Gauri, Do you have your Mercury along with a bunch of other ‘rude mouth’ planets and asteroids in nit picking Virgo? Sure it is an error though not significant in the context of what she was trying explain. But was it that hard for you to point out the error more politely?

    Even if you were only half a beginner in astrology, you should be thankful that experienced astrologers like Nadia are teaching us for free.

  11. Thank you Gauri for pointing out the error, it has been rewritten by Nadia and updated in the post.

  12. @Gauri
    Yes, thanks for your observations and feedback!

  13. @Marion
    And thank you Marion, as always, for your support. 🙂

  14. Hi Nadia,

    I have a question about mercury in synastry aspects. Does partner A’s mercury trine/square/opposition partner B’s outer planets act similar to your discussion with Marion about a natal chart? Let’s say Partner A’s mercury trines Partner B’s Uranus, in keeping with your discussion. Does Partner A’s way of speaking bring out Partner B’s quirkiness?? Or does she express his oddities well? I’m just curious how synastry her personal-to-his outer planets work ( and vice versa). Thank you.

  15. @Abby
    Partner A’s Mercury (their way of speaking/thinking) will activate Partner B’s outer planet energy. Whether it encourages that energy (the trine to Uranus might make the Uranus person feel that the Mercury person accepts their quirkiness) or challenges it (Mercury is not accepting of Uranus’ quirks) depends on whether the aspect is easy or hard. A hard aspect might push the Uranus person to act out, just because. For the Mercury person, their ideas will either be positively enhanced (say, given new ideas by a trine to Uranus) or challenged (disrupted by a square to Uranus).

  16. Sag Rising says:

    I have natal mercury in the 8th square natal pluto! Cancer on the cusp of the 8th. Lots of water/emotions. I can only have very “deep” emotional relationships when it comes to my personal life- nothing less interests me. Otherwise I’d rather be in my own company.

    Does mercury have a similar effect when it comes to the Solar Return chart? I ask this because this year my mercury is in chatty Gemini in the 5th conjuct Venus in Gemini in the 4th. Would this make me less emotional in regards to my relationships? Or, would it just appear that way on the surface and then I would go back to my “deep” ways (per my natal chart)?

  17. @Sag Rising
    You’ll feel your SR Mercury in the context of the SR house it’s in. If it’s in a relationship house (1st, 5th or 7th) then you would feel it in connection to relationships. If it’s in the 10th House you’ll feel it in the context of career, and so on. Natal influences are the still the primary energies, but SR planets are felt as temporary changes.

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