Tune from James Kinsley's The Poems and Songs of Robert Burns, vol. I (Oxford, 1968, p. 252):

X:1
T:HIGHLAND LASSIE O--
M:C
L:1/8
N:McLauchlin's Scots Measure
K:C
"Slowish"(ED)|C3 E (DC) (DE)|G2 D2 D2 (ED)|C3 E (DC) (DE)|
(GE) (DC)c3 d|(ed) (ce) (dcA) d|cA GE D3 E|
C3/2D/E F (GAc) G|E2 C3/2D/ C2||(ed)|c2 f2 (efg) e|
a2 (d3/2e/)d2 (ed)|c2 g2 (efg) a|(gf) (ed)c3 d|(edc) e
dcA c|(A3/2G/)F E D3 E|(CDE) F GAc G|E2 C3/2D/ C2|]