S.D. Codified Laws § 19-19-701 (2026) – Opinion testimony by lay witnesses.

If a witness is not testifying as an expert, testimony in the form of an opinion is limited to one that is:

(a) Rationally based on the witness's perception;
(b) Helpful to clearly understanding the witness's testimony or to determining a fact in issue; and
(c) Not based on scientific, technical, or other specialized knowledge within the scope of § 19-19-702.

Source: SL 1979, ch 358 (Supreme Court Rule 78-2, Rule 701); SL 2011, ch 234 (Supreme Court Rule 10-10 ); SDCL § 19-15-1 ; SL 2016, ch 239 (Supreme Court Rule 15-49), eff. Jan. 1, 2016.