No — and in most kitchens you don't want them to. Painting cabinets and walls the exact same colour can work in a small galley or a deliberately drenched, moody scheme, but in a normal kitchen it tends to flatten the room and make the units disappear. You lose all the lovely depth that good cabinetry gives you.
The approach that nearly always looks expensive is tonal layering: a deeper, more saturated colour on the cabinets and a quieter, lighter relation on the walls. Think Farrow & Ball Treron or Card Room Green on the units with Cornforth White or Ammonite on the walls — same undertone, different weight. Do the doors in an eggshell or a proper cabinet paint and the walls in a wipeable matt, and the contrast in both colour and sheen does half the work for you.
If you genuinely want a calmer, monochrome look, don't go identical — shift by a couple of steps. Little Greene French Grey on walls with a darker grey-green on the base units reads as considered rather than flat. And full colour-drenching (walls, cabinets and woodwork all in one colour) is a real trend, but it only works in a confident, characterful colour like Hague Blue or Studio Green — not a timid neutral, where it just looks like you ran out of paint.
The "but what about my worktop and splashback?" question is the one that actually matters here. Pick your cabinet colour against the fixed elements — the worktop, the floor, the metalwork — long before you fuss over the walls. Those are the hardest things to change.
Practical advice: for the cabinets themselves, spec a hardwearing finish — Little Greene Intelligent Eggshell, F&B's cabinet-grade options, or Bedec MSP over a Zinsser BIN primer if you're going over old factory units. Get that right and the wall colour is the easy bit.